How do teleport people automatic ?

So i am making a game ( takes all ill say) . I read some Lua books but i can't get this right. So here is want i'm trying to do : I made a nice Lobby where the players spawn and i made some maps , i'm trying to make the spawned players teleport to the map after a planned time ( 20 seconds) (Like in murder mystery 2) . I would really appreciate if you could guide me to trying do that or how murder mystery 2 teleports its players .