Because we're one of the best places to work in the UK - you can find out why here http://remarkable.group.shef.ac.uk/
How does someone get hired at University of Sheffield? What are the steps along the way?
Apply at the university website, if you are a student sign up to careers service and jobcentre emails and apply for any jobs posted. Also, keep on top of emails from your department as they do post quite a few internal part-time jobs for students throughout the year.