I volunteered, I just asked when I could start and was given an introduction the following week.
telephone call then onsite interview/chat to through legal stuff
Really easy done in 5 mins
Interview. Do your research before interview. Be positive. Can be working with volunteers who have issues, so must be a positive person to help pick the atmosphere up in the shop.
There is an induction followed by an application form where basics are needed like address, referees, reason as to why you want to volunteer etc.