How can I add a custom message and logo to my sign in page?

I have a premier subscription and I am trying to follow the instructions to add a Custom Sign In Message listed here: https://help.quickbase.com/user-assistance/?_ga=2.226310426.105621529.1535643166-1082726460.15338427...

However, I can't seem to find the "UI tab" referenced in step 2 (nor can I find anything that resembles the following steps throughout app settings).

This seems so simple and yet, I am unable to figure it out! I've customized headers, footers, etc. but can't locate a place to format the sign in page at all. I'm optimistic this can be done (especially given the section in Quickbase help). Please help!