Code (Text):

1. #This is a example because I don't know how yo join the mini game you can change this.
2. Command /join:
3.     Trigger:
4.         If {minigame::%player%} exists:
5.             Message "you already join the game"
6.         Else:
7.             Set {minigame::%player%} to true
8.             Message "you join mini game name"
9.  
10. Command /leave:
11.     Trigger:
12.         If {minigame::%player%} exists:
13.             Delete {minigame::%player%}
14.             Message "you leave mini game name"
15.         Else:
16.             Message "you are not in a game"
17.  
18. #idk how do you start the game but this is an example
19. Command /start:
20.     Trigger:
21.         Message "minigame started" to {minigame::*} # message all players inside the list
22.         Loop {minigame::*}:
23.             Teleport loop-value to {game} # you can set the game location
24. #set the game location
25. Command /setgamelocation:
26.     Trigger:
27.         Set {game} at the player's location
28.         Message "game location set at %{game}%"
29.