Welcome to the site!
Make sure to read all of the rules and take a look around the forums. You can find each forums rules on the top of each. There are lots of existing discussion threads, so take a look at those (if they're not dead of course) and feel free to jump in to some conversations you like!
There's plenty of announcements being made about tournaments and rules based stuff, so if you're interested in that just keep an eye out!
Also feel free to join the Discord. It makes asking questions a lot easier.