How to add search values to the browse function

Can someone help me with this?

I assume you mean the browse box on the all members page? From what I can tell, this is hard-coded and wouldn't be a simple change.

I want to make some changes to this box myself and I am going about it a few different ways.

What do you want to add? Keep in mind that this is a filter rather than a search function and it works best with predefined fields. And there are already three different search blocks (simple, advanced, quick) that you can customize through the Profile Fields builder.

Maybe you can just change your navigation to default to the search page instead of the browse page?

I just tried experimenting with changing the navigation and I don't think that would be a good option. If the top link goes to the people search, then you lose the people sub menu.