diff --git a/damastodon.py b/damastodon.py
index 8a296b8..981ca2f 100755
--- a/damastodon.py
+++ b/damastodon.py
@@ -10,13 +10,22 @@ import time
 import sys
 import re
 
+#configuration server
 api_url = sys.argv[1]
 save_position = "/tmp/"
 CLEANR = re.compile('<.*?>')
 botname = "@damastodon "
 
-firow = "🇻1️⃣ 2️⃣ 3️⃣ 4️⃣ 5️⃣ 6️⃣ 7️⃣ 8️⃣\n"
-colsx = "🇦🇧🇨🇩🇪🇫🇬🇭"
+#board appearence
+frstrow = "🇻1️⃣ 2️⃣ 3️⃣ 4️⃣ 5️⃣ 6️⃣ 7️⃣ 8️⃣\n"
+column = "🇦🇧🇨🇩🇪🇫🇬🇭"
+space="🟥 "
+white_norm="◽ "
+white_knight="⚪ "
+black_norm="◾ "
+black_knight="⚫ "
+empty="🟦 "
+
 
 def cleanHTML(raw):
 	cleanText = re.sub(CLEANR, '',raw)
@@ -30,68 +39,94 @@ def check_message(notification):
 			return
 		content = content[len(botname):]
 		saves = os.listdir(save_position)
-		if content.lower() == "help":
-			mastodon.status_post("Hello @"+account+" \nchallenge an user by writing to me\nCHALL <USERNAME>\nEx. \"CHALL @someone@mastdn.inst.wxyz\"\nThe challenger takes WHITE and begins the match.\nFor movements and jumps, write the coords separated by spaces.\nEx. \"A4 B5\" (normal movement) or \"A4 C6 D8\" (double jump)\nQUIT ends the match.\nCommands are NOT case sensitive..",visibility="direct")
+		if "help" in content.lower(): #Ask for help
+			mastodon.status_post("Hello @"+account+" \nchallenge an user by writing to me\nCHALL <USERNAME>\nEx. \"CHALL @someone@mastdn.inst.wxyz\"\nThe challenger takes WHITE and begins the match.\nFor movements and jumps, write the coords separated by spaces.\nEx. \"A4 B5\" (normal movement) or \"A4 C6 D8\" (double jump)\nQUIT ends the match.\nCommands are NOT case sensitive.",visibility="direct")
 			return
-		if not os.path.exists(save_position+account):
+		if not os.path.exists(save_position+account): #If there is no a savegame file, then lobby mode is activated
 			try:
-				challenged = notification["status"]["mentions"][1]["acct"]
+				challenged = notification["status"]["mentions"][1]["acct"] #If there isn't another account cited, then the request is malformed
 			except:
 				mastodon.status_post("Hello @"+account+" \n your request is not valid",visibility="direct")
 				return
-			if content[:5].lower() == "chall":
+			if content[:5].lower() == "chall": #Challenge someone, check if a savegame is already existing
 				file_save_white = [sv for sv in saves if account in sv]
 				file_save_black = [sv for sv in saves if challenged in sv]
-				if len(file_save_white) > 0:
-					mastodon.status_post("Hello @"+account+" \n you're already playing a match",visibility="direct")
+				if len(file_save_white) > 0: #We are playing a match
+					mastodon.status_post("Hello @"+account+" \n you're already playing a match",visibility="direct") 
 					return
-				elif len(file_save_black):
+				elif len(file_save_black) > 0: #Our opponent is already playing with someone
 					mastodon.status_post("Hello @"+account+" \n the user you challenged is already playing a match",visibility="direct")
 					return
 				else:
-					open(save_position+account,"w").close()
+					with open(save_position+account,"wb") as f: #The request is valid, writes a savegame with the first element as False, that marks that the game isn't started yet
+						pickle.dump("WAIT",f)
 					ident = mastodon.status_post("Hello @"+challenged+" \n@"+account+" challenged you to a match of draughts! Answer \n@"+account+" OK\n to accept the chellenge or \n@"+account+" NO\n to cancel.",visibility="direct")
 					return
-			elif content.split(" ")[1].lower() == "ok":
+			elif content.split(" ")[1].lower() == "ok": #The opponent accepted the match
 				try:
-					challenger = notification["status"]["mentions"][1]["acct"]
+					challenger = notification["status"]["mentions"][1]["acct"] 
 				except:
-					mastodon.status_post("Hello @"+account+" \n your request is not valid",visibility="direct")
+					mastodon.status_post("Hello @"+account+" \n your request is not valid",visibility="direct") #Somehow, the opponent answered with only one account
 					return
-				os.symlink(save_position+challenger,save_position+account)
+				try:
+					with open(save_position+challenger,"rb") as f:
+						start = pickle.load(f)
+				except FileNotFoundError:
+					mastodon.status_post("Hello @"+account+" \n unfortunately, your savegame is corrupted or missing",visibility="direct") #The file has moved or corrupted
+					return
+				if start != "WAIT":
+					mastodon.status_post("Hello @"+account+" \n your request is not valid",visibility="direct") #The user that challenged us is playing a game with someone else
+					return
+				os.symlink(save_position+challenger,save_position+account) #Linked the two savegames together
 				board = dama.init_board()
 				with open(save_position+account,"wb") as f:
+					pickle.dump("START",f) #Now the game has started
 					pickle.dump("@"+account,f)
 					pickle.dump("@"+challenger,f)
 					pickle.dump(False,f)
 					pickle.dump(board,f)
-				mastodon.status_post("◾: @"+account+" ◽: @"+challenger+" \nturn ◽\n"+dama.draw_checkerboard(board,space="🟥 ",white_norm="◽ ",white_knight="⚪ ",black_norm="◾ ",black_knight="⚫ ",empty="🟦 ",frstrow=firow, column=colsx),visibility="direct")
+				mastodon.status_post("◾: @"+account+" ◽: @"+challenger+" \nturn ◽\n"+dama.draw_checkerboard(board,space,white_norm,white_knight,black_norm,black_knight,empty,column,frstrow),visibility="direct")
 				return
-			elif content.split(" ")[1].lower() == "no":
-				os.remove(save_position+content.split(" ")[0][1:])
-				mastodon.status_post(account+" you cancelled the challenge from "+content.split(" ")[0],visibility="direct")
+			elif content.split(" ")[1].lower() == "no": #The opponent refused the game
+				try:
+					challenger = notification["status"]["mentions"][1]["acct"]
+				except:
+					mastodon.status_post("Hello @"+account+" \n your request is not valid",visibility="direct") #Only one user in the message
+					return
+				os.remove(save_position+challenger)
+				mastodon.status_post("@"+account+" you cancelled the challenge from @"+challenger,visibility="direct") #Game is cancelled, free to challenge someone else
 				return
 			else:
-				mastodon.status_post("Hello @"+account+" \nI can't understand your command or you're not in a match.\nWrite HELP to see the list of available commands.",visibility="direct")
+				mastodon.status_post("Hello @"+account+" \nI can't understand your command or you're not in a match.\nWrite HELP to see the list of available commands.",visibility="direct") #Every other command for the lobby ends here
 				return
-		else:
+		else: #We are in a game, so movements are parsed and lobby commands are disabled
 			with open(save_position+account,"rb") as f:
-				black = pickle.load(f)
-				white = pickle.load(f)
-				turn = pickle.load(f)
-				board = pickle.load(f)
-			if content.lower() == "quit":
+				start = pickle.load(f)
+				if start: #The game is started, load other parameters
+					black = pickle.load(f)
+					white = pickle.load(f)
+					turn = pickle.load(f)
+					board = pickle.load(f)
+			if (start == "WAIT"): #The game is not started yet
+				if "quit" in content.lower(): #Game withdrawn
+					os.remove(save_position+account)
+					mastodon.status_post("Hello @"+account+" \nthe challenge has been withdrawn.",visibility="direct")
+				else: #Lobby is disabled if a challenge request is active
+					mastodon.status_post("Hello @"+account+" \nyou have already challenged someone, type QUIT to withdraw,",visibility="direct")
+				return
+			if "quit" in content.lower(): #The game is quitted
 				os.remove(save_position+black[1:])
 				os.remove(save_position+white[1:])
 				mastodon.status_post(black+" "+white+" the match was cancelled.",visibility="direct")
 				return
-			if (black == "@"+account and turn == 1) or (white == "@"+account and turn == 0):
-				board = dama.valid_move(content.lower(),turn,board,inversion=True)
-				if board == -1:
+			if (black == "@"+account and turn == 1) or (white == "@"+account and turn == 0): #Check if the turn is right
+				board = dama.valid_move(content.lower(),turn,board,inversion=True) #Function dama.valid_move parses the input for couples of letter and number
+				if board == -1: #We made an invalid move
 					mastodon.status_post("@"+account+" \nInvalid move.",visibility="direct")
 					return
 				else:
-					with open(save_position+account,"wb") as f:
+					with open(save_position+account,"wb") as f: #Save the updated board
+						pickle.dump("START",f)
 						turn = not turn
 						pickle.dump(black,f)
 						pickle.dump(white,f)
@@ -101,20 +136,20 @@ def check_message(notification):
 						colour = "◽"
 					else:
 						colour = "◾"
-					winner = dama.checkWin(board)
-					if winner == (False,False):
-						mastodon.status_post("◾: "+black+" ◽: "+white+" \nturn "+colour+"\n"+dama.draw_checkerboard(board,space="🟥 ",white_norm="◽ ",white_knight="⚪ ",black_norm="◾ ",black_knight="⚫ ",empty="🟦 ",frstrow=firow, column=colsx),visibility="direct")
+					winner = dama.checkWin(board) #Check for winner
+					if winner == (False,False): #No one is winning yet
+						mastodon.status_post("◾: "+black+" ◽: "+white+" \nturn "+colour+"\n"+dama.draw_checkerboard(board,space,white_norm,white_knight,black_norm,black_knight,empty,column,frstrow),visibility="direct")
 						return
-					else:
+					else: #Someone won
 						if winner == (True,False):
 							winner_t = "WHITE"
 						else:
 							winner_t = "BLACK"
 						os.remove(save_position+black[1:])
 						os.remove(save_position+white[1:])
-						mastodon.status_post("◾: "+black+" ◽: "+white+"\n"+winner_t+" WINS!\n"+dama.draw_checkerboard(board,space="🟥",white_norm="◽",white_knight="⚪",black_norm="◾",black_knight="⚫",empty="🟦",frstrow="0🇦 🇧 🇨 🇩 🇪 🇫 🇬 🇭 \n"),visibility="direct")
+						mastodon.status_post("◾: "+black+" ◽: "+white+"\n"+winner_t+" WINS!\n"+dama.draw_checkerboard(board,space,white_norm,white_knight,black_norm,black_knight,empty,column,frstrow),visibility="direct")
 						return
-			else:
+			else: #We moved in a wrong turn
 				mastodon.status_post("@"+account+" \nIt's not your turn.",visibility="direct")
 				return