In order to be granted a permission to enter or remain in the UK, applicants must score enough points in the relevant categories. Points are awarded based on the documents submitted in support of your application.

The UKVI has produced a Working after your Studies guide to explain the different options for those wishing to remain in the UK after completing their studies.

GCU is a licensed Sponsor under Tier 4, and this is the category under which you will need to apply. Tier 4's points scoring system is relatively simple; you must be awarded 40 points in total, and the only way to score these as follows:

Possession of a valid CAS (see guidance) 30 points 
Possessing the funds (maintenance) to pay your course fees and living costs 10 points

You should remember that simply scoring enough points does not guarantee your application will be successful; you can still be refused a visa for other reasons. For more information on the system, see the UKVI's Immigration Rules: Part 6A

For information on how to apply for Tier 4, click on the appropriate pages on the left hand side.