How does TeamXp know a user is legitimate to play that simulation? 
To identify your player of just to know that a person is legitimate to play your simulation, you could register them beforehand and allow only whitelisted players to your exercise.
If you can’t or you don’t want to register your players you could create a special code at the beginning for them to type. You can do this by using one of these options: passcode, passcode unique to player, single passcode. Know more in this article.