“Open to the needs of the Air Force”

So I have started speaking through text with a recruiter for the AF. I don’t personally know anyone in & am doing all of my research here online.

Why does everyone say they picked a job? I am aware of the job list & how you choose 10, but then what? Do you wait for an opening on any of ur chosen jobs then go with the first to come?

Also, my recruiter told me that since I need a waiver I will have to be open to the needs of the AirForce. In the questionnaire it mentions special warfare, mechanical, electrical, & security forces interest. Does this mean these are my only options? I will obviously speak to him more about this & ask plenty of questions, but I wanted some info & opinions from others first.