You fill out and application online or through the venues office. You submit it and wait for a call back from the venue. One of the hiring managers opens and reviews applicants applications. If the application satisfies the requirements the applicant is called to set up and in person interview with the manager.

I had applied for stagehand, they didn't have openings for that so they sent me over to interview at this department. Person interviewing was very nice and chill. Seemed like they just wanted people there who wanted to be there.