You are asked to visit the agency to complete employment forms and to meet with a recruiter. They are the ones that go over the position you will be submitted for based on what they feel your qualifications are best suited for. They then may or may not send you to interview with the company you will be working at, sometimes they just tell you when to report for your starting date (I assume that this is how the employer prefers the hiring selection process to be, is to let the agency choose who they feel is the best match for the position) once you have interviewed or started the job, it's up to you to make it work and get hired!