You may sign up only after you submit your application.
Spots are first come, first serve.
Your recommendation letters can be from past employers, professors, family members, friends, etc. We recommend that you select someone who really knows you and can articulate your strengths. Thus, staff opinion is already included in this process. Often, we have too many qualified applicants and not enough available positions. However, if a vacancy does arise on staff, alternates are the first group considered for filling it.