You can join as a Civilian Instructor, which has no minimum monthly commitment, unlike uniformed staff. Talk to the Squadron Commander in the first instance to see what they need and what you can offer. Alternatively, you could join the Squadron's Civilian Committee, which has an overarching responsibility for fund raising and welfare of cadets and staff. You'll need to have a DBS clearance (previously CRB) if you want to become an instructor, which the Squadron will arrange if/once you've agreed to be a staff member. I was an instructor for 29 years and it was an absolute privilege to have been so.