I figured out that I have to use /join name to actually start the arena.
But how do I now link that with the warps?
Right now I have the warp setup to tp the player to a invisible walkway above the arena, but the game does not start.
I have a feeling it has something to do with the option to add user and server commands
"Command called to player": "example.run {userID}",
"Command called to server": "example.run {userID}"
I would think that i would need the command "join arenaName" to run everytime someone enters the warp, but i am not sure exactly the syntax needed for that to work.