You will only need to login as a player on Teach Your Monster to Read. All other apps it is best to use your user account (email/password) to login.
I'm using an account from a school / a teacher
If your player details were given to you by a school or a teacher, it's best to reach out to them to get your login recovered.
I'm using my own account
If you're using your own account and you've forgotten your player login details, here's how to get them back:
Log in to your user account
Find the player you want the details for
Click on the 3 dots next to them
Download the password card for the player