Hi carla, i can give you a few tips on the air gybe and vulcan.
just a slight note: an air gybe is slightly different from a vulcan, in a vulcan you stay in the footstraps untill the end of the move but with an air gybe you take off out the straps when you take off and land. in my opinion an air gybe is a bit of an 'old style' move so you should probably go for vulcans
first of all to do vulcans i would say you need to be competent at a few things:
1. able to pop the board going downwind
2. bieng able to do basic light wind freestyle e.g. helitacks, sail 360's
3. able to sail switch-stance IN the footstraps, a good exercise is switch-stance flare gybes and switch stance non-planing duck gybes
getting your kit setup right for freestyle is quite important. i personally put a little more out-haul and a little less downhaul on my sails for freestyle and generally sail them in far less wind than i would for blasting as a result usually ending up doing a bit of schlogging. as far as my boards go i have my footstraps loose enough so i can get by feet right over the centre line and somtimes have them a bit past the cetre line, and use the smallest fin i can get away with. i usually move the mast track a little further forward as i believe it makes sliding a little bit easier and position my foot straps on the most inboard and forward position possible. on my 86 ltr freestyle board i genarally sail it with a 5.2 and a 21cm fin in about 17 knots if the wind is consistent and put a 23cm fin in if its a bit gusty i am 63 kilos.
the vulcan comprises of a few steps these are
1. sail fast when preparing for the vulcan as it makes popping and sliding easier and also makes the sail lighter
2. pop the board a bit off the wind
3. similtaneosly let go with your back hand,throwing yourself around, bring your front hand across you(same as a tack) and grab the new boom side with your old back hand and grab the boom with your old front hand which is now your new back hand, doing this all whilst rotating around the nose
4. slide backwards back winded
5. suddenly change from bieng back winded to bieng switch stace going the other way ,when you stop sliding. remember to lean to windward as you change sail side
6. gain a little bit of forward momentem on your new tack, then change the feet round
hope this all makes sense, just remember the vulcan is not very hard and is very acheivable you just need to be dedicated and go out in light winds and practice the key skills such as: switch stance sailing, sailing backwinded e.t.c and you will have it in 2 weeks