Go to the participants of your game.
The easiest option is to give your players the game pin code, which they will use to login to the game. In this case the teams will create their own team names.
It’s also possible to create your teams ready and give the teams their player codes when you start playing.
The login process for the players, when they login with a game pin code:
The players login on seppo.io → Login to game → Login as player → Enter pin code → Choose a name for the team → Get your player code
If the players have a player code, the last two steps are not needed.