Welcome to the seadoo forum toga456. It depends as exactly what the dealer did. Was it a seadoo dealer. I'm just guessing a seadoo dealer did it, so I'll summarize it up for you...
To properly de-winterize your seadoo, Change the spark plugs, charge up the battery, start it up on the hose to allow all the anti-freeze to not get dumped in the water on your first use. You should have used environmental safe anti-freeze, but not everyone is aware of that fact. Collect the old anti-freeze and dispose of it properly. Remember to lube the throttle body also. Check all the cables and the Jet pump gate for operation. You should be all set after that
You should add your seadoo description to you avatar for future reference if you have any more questions....
Karl