Jobs for nurses range from patient care to non-patient care. It often will depend on your hospital as to what your job duties are.
On the inpatient units - which you will have clinical on in school - you do everything for the patient. Give meds, baths, physical exams, teach the patients. You basically plan the care, implement the care, teach the patient about his care and get him involved in the care. You keep the patient alive.
In some operating rooms, nurses assist the doctors and get to dig inside people and hold instruments. In others, nurses only circulate which means they position the patient on the operating table, clean the operative area, act as a "go-fer" for the doc and scrub tech, work with the various machinery used in the OR, document what goes on and basically keep things running smoothly.
In PACU, you monitor the patient after surgery until they wake up enough to leave or go to a hospital unit. Usually you are giving lots of meds for pain and nausea.
In cath lab, some nurses may assist the doctor with the procedure and scrub in, others simply do the same thing as a circulating nurse in the OR.
Radiology nurses start IVs and give medications while monitoring patients having catscans, MRIs, or other tests.
Case manager nurses know about why patients should be in hospital, and make sure the patients are getting the correct care needed in hospital and at home. They help coordinate nursing, medical, physical, occupational therapies. They also work with insurance companies.
Educators teach the staff how to do certain procedures and keep them obviously - educated.
Since you don't have any nursing school experience yet, it is hard to really tell you all about what nurses do. Once you have clinnicals you will have a better idea. And then you may have an idea of what specialty you want to work in. Perhaps someone may come along with some websites that may have more of an overview of various specialties.