Take part in a free singing class before you decide to join Rock Choir. These are either at a normal rehearsal or, in the case of new choirs, at a special pre-term taster session.
There is no audition and no spotlight will be shone upon you at the taster. It is very much about you deciding whether you like Rock Choir and wish to join.
When you attend, you will take part in a normal rehearsal and afterwards you should talk to your Choir Leader about the joining process.