I want to do a text search -- the kind you do with the search bar up top -- but I can't for the life of me figure out how to narrow down the results, like in Browse.

Hypothetical example: Let's say I want to search for games about... uh... Iunno, deserts? I wanna see all the games that have "desert" somewhere in its title or description (regardless of tags)... BUT narrowed down to ones I can play on my Mac laptop. In addition, I'd like to limit the results to free games only.

How do I go about this?