Google Drive on MacBook Air M3

I need some help with Google Drive on my MacBook Air M3.

I've started learning Catalan. My teacher is sharing course materials and assignments on Google Drive. Trouble is, I can't access them. When I click on a document she shares by e-mail, I get the message "Access denied" and an instruction to "Request access, or switch to an account with access". I only have one Google Mail account. The same happens on my iPhone 14.

My teacher tells me that I should be able to see the documents she shares on my Google Drive under "Shared with me". But the only document I have under "Shared with me" is the lesson calendar sent by the language school from its own e-mail address. I don't even know how it got there.

Would it help if my teacher shared the documents to my Google Mail account rather than my icloud email address?

Could somebody explain what is going on and how I can view the documents shared by my teacher on my Google Drive?

[Edited by Moderator]