Tribal ESD

How do I apply for a student visa to come to the UK? How do I extend my current student visa? I have a tier 4 visa, but want to change my course. What do I need to do? My current visa expires more than 28 days before the start of my new course, can I extend my visa in the UK? How long will it take for my visa application to be processed? My visa is for another institution, can I use it to study at the University of Exeter? There is a mistake on my visa/Biometric Residence Permit (BRP), what should I do? Do I need to register with the police? How do I do this? Are there any special visa rules if I am under 18? What should I do if I lose my visa/passport? I have a Tier 4 visa. Can I attend graduation on this visa? I need to interrupt my studies or withdraw from my programme, will this affect my Tier 4 visa?