Your best bet is to do a resort course, known by PADI as Discover Scuba Diving. Involves less than an hour of video/classroom & being shown the gear you'll be using, followed by maybe 1/2 hour going over a few basic safety skills & hand signals in shallow water you can stand up in. Then you're off for a dive at a real dive site. The whole thing takes around 1/2 day.

If you want to do it again during your holiday then you don't do the training part again.