In order for the tumblr mobile app to redirect to something, it has to be a post e.g. /tagged/about - It can’t be an actual page e.g. studyingbrains/about (this won’t work).
A couple extra pointers:
The accent colour (in the mobile app editor) is the colour of your links.
Try to use obscure tags for “about” links and “my post” links. Otherwise random posts with the words will pop up. For an about page maybe tag the post as “ab0utm3″ then other posts on your tumblr with the words aboutme won’t be shown.
The above applies to original content too if you tag your stuff as “personal” all posts with that word will pop up (even other users that you’ve reblogged). Come up with obscure tags for mobile links (this makes it easier for followers to navigate).
When editing your tumblr theme, links tend to break and need to be reentered. Keep that in mind. Check your links every time, after you edit.
You can still write in the description box, just write before and after the links. e.g. “Brains | UK | About|”
You can add as many links as you can fit!
You can add links via the desktop theme editor (I prefer this way), by writing in the description box:
