it really depends on the library! I work at a library on campus and love it, but ik some libraries have stricter policies than others (able to do homework v.s. not able to do homework, flexible hours, etc.). 

My biggest advice is to check hire-a-dore (the student employment portal) consistently throughout the summer once you get access to it, since library positions are pretty popular and go quickly. If you have any more specific questions feel free to dm 💌