The hours you are permitted to work will be clearly indicated on your online Immigration Status (e-visa).
As a Student Route visa holder the types of work you can undertake are:
- Paid, unpaid and voluntary work
- Paid and unpaid work placements undertaken as part of a course of study or period of study
Student Route visa holders are restricted from the following:
- Self-employment
- Engaging in business activity
- Providing services as a professional sportsperson or entertainer
- Take a full time, permanent position
To further understand what 'self employment' and 'business activity' means please go to the FAQ titled: Understanding Self-Employment and Business Activity.
UKVI also confirms that 'paid and unpaid work placements undertaken as part of a course of study' are separate from 'paid or unpaid employment', so can be done simultaneously.