It only takes 5 minutes to register, and you can use this free automated service provided by Jisc, which makes it easy for you, and collects the required voter registration information passing that to the relevant Electoral Registration Office on your behalf: https://www.gre.ac.uk/studentvoterregistration
To vote in the elections taking place on 6 May you must register by midnight on 19 April. You can also register to vote on the gov.uk pages, you can also check which elections you're eligible to vote in.
Find out what elections are taking place on 6 May
You can find details of the elections being held, and the candidate information on the Electoral Commission website, by entering your postcode.
