Elections are comming on 6 May 2021 – make sure you are registered to vote for a sustainable future well in advance. This can be done entirely online, see https://www.gov.uk/register-to-vote .
Also this year more than ever it’s important to get a postal vote, this tells you how – https://www.bristol.gov.uk/voting-elections/postal-voting .
For postal voting they need your signature and time to get it on the system, so the application needs to be received by 5pm 20-April. You can print the form or get it sent to you, then sign, and scan/take a pic and email or post it back. You can ask for a postal vote until further notice, so you only have to do this once (until you register somewhere else). Once it’s done they’ll send you ballot papers for every election and you’ll always have the option of voting by post or taking it to the polling station.
You might even consider lobbying to make it possible to vote online for future elections. A 2015 commission recommended that everyone should have the option to vote online by 2020, but this still hasn’t happened. This would increase the number of younger people voting. Here’s the commission’s view: http://www.digitaldemocracy.parliament.uk/chapter/10-elections-and-voting .