Logging into the Staging Site

How do I get from my “staged” home page (w/orange menu bar at the top) to the back-end in order to start updating my site with a new theme?

If I click on any menu item (in the orange bar), I am asked to login to WordPress, and I’m taken to my live back-end (purple background)

My login url for WP-Staging is: https://www.nlna.org/nlna-update/

I’m lost, and am also a novice user, so please answer as if I were a ten year old.

Thanks! -kat.

The page I need help with: [log in to see the link]