how do people play in the open qualifiers?

https://www.vlr.gg/event/1309/challengers-league-north-america-split-1/open-qualifier
how do people just like play in this tournament with a team? is there like a website you just submit yourself into? ive always wondered

are all vlr nerds casuals like you?

battlefly i think

so you can play in this tournament with a team by