Hello Annee,
Club med does offer a resort diving course. However you will much more relaxed and enjoy your diving experience better if you were to take a diving course before hand and also do a few dives locally if you are able.
The diving was pretty good while we were there. We saw some hammerheads, reef sharks, a few turtles, lots of barracuda and a few rays.
The dive crew is pretty good and you can opt to have a guide to go with you if you would like.
Hope this helps.
Heidi