If you feel like you would like to play with more players to maximize the fun, they are always welcome to join the game. However, players who started first will need to finish the game, or the VIP might need to restart the game from the ☰ (Settings) menu. This will return current players to the lobby, where your friends or family can scan the QR code to join the next game. 

If you need help connecting your phone or tablet as a controller, please see:

How can I connect my Android phone or tablet to use as a game controller?
How can I connect my iOS phone or tablet to use as a game controller?