Easy process just be yourself and let them know the skills you bring to the table. It is one interview and the work is really easy. You meet directly with the person you are working under.

i applied online and, after a few months passed, was invited for an on-site interview. i was interviewed by a would-be coworker and manager at the same time. coworker was polite but manager was pretty rude when he asked me questions. i didn't like his attitude at all. it was difficult to strike up any kind of conversation/"get the ball rolling" since the manager definitely did not want to be in that room with me. very dissatisfied.