The process is fairly simple. If you see a shout in town from a recruiter you can click their name and ask to join more details. Afterward they may invite you to party and go from there.

Then there are applications, if you see someone in an fc somewhere can open up their company profile and see if they are accepting applications. If they are click that option and fill out the box and submit it. The appropriate members in the fc will get notified when they log in.