The mobile app supports logging in using a Riverside account with an email address and password. If you usually use a Google Account ('Log in with Google') or your Apple ID ('Log in with Apple') in your computer browser and need to join a Studio from your mobile device as a Host, disconnect the Google Account or the Apple account and reset your password to create a new one.
Step by step:
Reset the Riverside password for the email address.
This creates a new, dedicated Riverside password.
You can use your mobile device to join a Studio as a Guest without logging in. Read more.
For functions like the sidebar chat and sharing your screen, use a computer to join the Studio. More Studio functions of the Host and Producer are available on a computer than on a mobile device.