All you need to do is remix the project, and sort the contestants from best to worst. The S-tier is where you put your favorite contestants, and the F-tier is where you put your least favorites. And then there are tiers in between if you like/dislike a contestant, but they're not your favorite/least favorite.
*These rankings are not what I think of the contestants!!! I just put them where they are because I needed a place to put them!!!*