Can't View Thunderbird Account Settings

Afternoon...

I am running T'Bird 68.xx (I think - I don't want to view "About" because I don't want to upgrade)

This is my dilemma...I would like to change my server settings to be prepared for the May 30th deadline for OAuth2 authentication, but I can't view account settings on any of my 3 Gmail accounts.

All I can view is a small dialogue box with the name of the account (my email address) and "account actions", nothing else.

I fear that if I can't get to the full menu of settings, I will loose everything come May 30th.

What can I do to view the entire list of settings?? The list was there when I set up Portable Thunderbird, a long time ago, but there is simply nothing to show now except what I just mentioned, this very small dialogue box.

I can't lose Thunderbird access - I refuse to use web mail. Google, unbelievable hypocrites.

Thank you, in advance.