so im trying t o make a minigame that players can join and i have some problems getting the player into my variable

Code (Text):

1.  options:
2.     {event.players}: %{joined.event.players}%
3.    
4. command /eventstart:
5.     trigger:
6.         teleport {event.players} to {event.respawn}
7.  
8. command /eventjoin:
9.     trigger:
10.         add player's name to {joined.event.players}
11.         send "&a&lSUCCES &8du joined &bSnowball-event"
12. [CODE] if you have any idea what i could do so they can get teleported and get their permissions