If you are a student (undergraduate or postgraduate) of Imperial College, then you are eligible to join all Union clubs. If not, please visit this page for more information.
Next, decide which club or clubs you are interested in (remember there is no limit to how many you can join) and then purchase your membership online.
If online purchasing is not your thing, then there are several other ways for you to become a member of a club.
Peruse the Freshers Fair maps and find out where the club or society you want to join is located. Go to that stand and say "Hi". Write your name and contact details on their sign up sheet, and they will be in touch with you soon after with details of the first meeting/trial/event of the year.
Contact details for each club or society can be found by clicking on the links in the A to Z list or looking them up in the Clubs & Societies Handbook. You can also find out contact details by asking at the Student Activities Centre, which is located in the East Basement of Beit Quad.
Spy one of the club or society posters and turn up to a meeting/event/session!