They decide which job they are going to interview you for out of the three jobs you choose on your application. It is rarely the first job you choose. The interview differs slightly if you are a new staff member or returning. If you are a returning staff member you will be asked questions relating to your previous experience and how you would help new staff members. I did get an offer, but I declined because they refused to allow me to go on a trek with my troop that had been canceled twice over 4 years.