How to register for open qualifications
Most of the time the links get posted on twitter (i.e https://twitter.com/projectvgg/status/1745493274549244309 and https://twitter.com/valleague_ne/status/1742561455537586543 for the 2 ongoing ones)
Id recommend looking for an active esports server in your region, both for finding teams/pugs and just since people tend to link signups there
I havent been active in the actual pro part of valorant for a while now so idk if it changed/what servers are popular atm so youd just have to ask around