“On-campus” means you can work at all the buildings on your school campus. If your school has more than one campus, you may only work at the campus where you’re studying in most cases.
You can work at other locations if
- you’re working as a teaching or research assistant and
- your work is strictly related to a research grant
In this case, you may work at a library, hospital or research facility associated with your school, even if they’re outside the campus.