Through FAFSA you are awarded work study scholarship, you are able to apply to desk jobs wherever on campus. As a work study job you are able to complete your homework assignments if the time allows while you do clerical/customer service duties in the office
There is a process which can really take awhile.
It ranges from a short 2 weeks mostly concerning internal hires and transfers, up to a lengthy 2 months concerning external hires.
If you are an undergraduate there are numerous volunteer opportunities as well as paid positions (many over the summer). The qualifications needed include: being in the top of your class, and possessing the characteristics indicative to being a researcher; creativity, imagination, persistence, and analytical skills.
As a Graduate Student, you must be accepted into the Grad School, and demonstrate the same characteristics mentioned above.