I got an invitation email. How do I join my program?

Tap Open your invitation in the email, then sign in with the same email address the invitation was sent to. You'll see "Your instructor has added you to" your class, with a Join button. Tap it. You're in.

The page says "not found"

You're signed in with a different email than the one your instructor invited. Sign out, and sign in with the address the invitation came to.

If that's an address you don't use, ask your instructor to re-invite the one you do, or change your email to match: How do I change my email address?

I never got the email

Check Spam and, on a school address, your quarantine digest. Your instructor can re-send the invitation from their roster. Once you sign in with the invited address, the invitation also appears as a notification, so you can accept it there even without the email.

I'm in two classes

You'll get two invitations and have two records, one per class. Accepting the second doesn't touch anything you've logged in the first.

Don't sit on it

An invitation that stays untouched for 90 days is removed. Accept it when you get it.