If you have student immigration permission that allows you to take employment, you can work up to 20 hours or up to 10 hours a week during term-time, but, you must not be self-employed or take a permanent full-time job.
However, you should be able to pay your tuition fees and living costs without having to work in the UK and you should not rely on money from work in the UK.
For more up-to-date information on working in the UK while you study, please consult the UK Council for International Student Affairs (UKCISA).