Creating a loging screen with face scanner

Hi, im new at MIT app inventor and i cant solve this can you guys help? Like i cant create a login screen its need to be like "login or sign up" please help.

i think its not what am i searched for.

And you saw that in 2 minutes? We have multiple topics about logins and signups. Look at the topics that @ABG showed you. Then try something and show what you have tried if it doesn't work.

If you are dead set on face scanning for your login, you have a big search ahead of you in