I would encourage you to read the Primer and the FAQ to cover the most basic… uh, basics. :P If you have some more specific questions feel free to ask them. Even if I can't help, someone will.
As for the 'how it actually works': you get to know other people, get yourself known, join in on the conversations and just keep in mind that it's better to write something longer/more insightful than "this is so cool" or "you are a moron". Either of those can only be improved by further context and perspective. Do keep in mind that as with most small communities it's a rather slowly paced place. On Reddit, you might not get five minutes without getting notified about a response. Here it gets much more leisurely.
Also, if you'll find an interesting topic that was created months or years ago, it can still be 'revived' and get other people to participate. Hubski doesn't block you from commenting by locking older posts in a read-only fashion.