XF 1.5 Change "Login or Sign Up" button at top to a link

Hello! I was wondering if I could get any help with changing the "Login or Sign Up" button at the top of my forums to just redirect to a link I set. I want to make it so players can only login with Steam instead of standard Xenforo, for a few reasons. I couldn't find anything for this, thanks in advance!
Last edited:
Clarification & Bump: I want to get rid of the popup menu form when you click "Login or Sign Up" at the top of the page, I just want it to act as if you clicked a link.