Why there are player in forum that 'non-existing'?

That means they are banned

how to make duel room, betting server and private room?

Duel room:
By typing /duel <tc> you can set the server to duel mode, you will duel for the amount you put in <tc>

Betting server:
You do need commands to make a betting server, but to advertise it and make it better you can:
1. Type /desc <text> to change the name of the server in the lobby.
2. Type /motd <text> to set a greeting message when people come in to the server (can be used for explaining rules, etc)
3. Type /betframes <number of turns> to set how many turns before people will not be able to bet for the round.
4. /minbet <tc> to set the minimum amount players can bet on a person.
To actually bet, type /bet <tc> <player>

Private room:
Type /passwd <password> to set the server in private mode, people will not be able to talk or get out of spectate unless they type /pass <password>

thank you so much star, I appreciate what yo tell me. thx

Remember to not put the "<" and ">".

No problem, if you need any further help, pm me

^ This.