fresh petrol (thats if you left any in) warm it up and it should be fine
but , have you run it up occasionally ?? if not i would be very very very careful, even better trailer or van it to the bike shop and get them to change the belts because if i remember Pyschlist correctly, after 3 months of standing idle they will have lost their flexibility will have begun to take the shape(if thats the correct wording) of the way they are on the pulleys, and may snap !! and that would be very expensive
.
So as i said book it in for a belt change and either ride it very carefully to the shop or trailer or van it .
of course i am no expert so expect someone will be along soon to correct me