The CO of the cadet corps/squadron you wish to volunteer with will have the information you seek, but I can give you a basic summary:
Basically, you will be a volunteer and relinquish any Class A, B, or C pay eligbility while parading with the cadet corps. I do not believe Reg F or P Res pers (that are not CIC Officers) can assume slated position, and thus be paid even if you assume duties that normally would consume a paid slate. You're always welcome to do a Component Transfer to the Cadet Instructor Cadre for 21 days of pay of year and no benefits (exception pension)...heh,heh. ;-)
You will also have to have an ERC completed, if one hasn't been completed in a while - yes, they are good for 10 years, but the Cadet Detachment must cross it's "I's" and dot it's "T's". You cannot supervise cadets alone without one, otherwise an ERC cleared Civilian Instructor or a CIC Officer must be in your presence (mostly a formality).
Mostly it's just having the CO fill out the proper paperwork and making copies of certain documents (SIN, PEN, Marraige Cert...etc) and having Det process it so they know you are on strength as Adult Staff for the cadet corps...liability issues. There is about 5 or 6 forms in all, plus the copies of your requested documents, as well as I believe a copy of certain parts of your Pers Record that confirms you are a member of the military, and what qualifications you may hold.
You will also need paperwork to take to your Unit, basically saying it's okay for you to parade with the corps, and in doing so, if you request, wear your uniform. Reg F Pers may not need permission for their uniforms, but P Res Pers do...but you still must make your COC aware you are parading with a cadet corps. It's just good common sense.
Talk to the CO of the cadet unit, and inform your COC of your intentions...that will get the ball rolling.