I am just going to copypasta what I answered for someone else who asked the same thing earlier this month:
So there is something in the US every spring called 'March Madness' which is widely used for a Basketball championship. Teams get put into brackets and play games against each other, and the winners advance up the brackets until a final showdown.
Back in 2011 I wanted to bring more visibility to the HTTYD-fanarts group as well as promote active artists, writers, cosplayers, craftspeople so I took the concept of March Madness and applied it to creators in the HTTYD fandom on DeviantArt.
If you look at the brackets in this gallery, you can see how it works, polls are put up so people can vote for their favorite creator and whoever has the most votes be the end of two days, advances up the bracket.
To get qualifying creators they must have been active since last March Madness (created at least 1 HTTYD-themed original deviation) and have at least 5 works in their gallery. We took nominations for about 2 weeks before march and put any of those qualified nominations into a list - almost always I have to pull from 'reserves' a separate list of creators that qualify but weren't nominated, so I can fill up the brackets. I put the names through a randomization to get the matches of who vs who.
I hope that explains it, let me know if you have further questions.