Congrats.
Learn the camera in the auto mode then go to the manual mode.
Practice using manual F stops and shutter speeds for macro shots using the built in strobe. Example: F6.3, 1/200 shutter speed, ISO 70. Get use to turning the onboard strobe power up/down as needed depending on the color of the subject etc.
Experiment on how close you can get without the on-board strobe being in the photo.
Practice calibratng your white balance off a dive slate for those non-strobe shots and the respective F stops, shutter speeds and ISO setting that goes with them. Example: sunny day, blue water, great vis, 60 foot depth = F4, shutter speed 1/80, ISO 100 or less if possible. Picture too dark, try lower F stop number. Still too dark try ISO 200. That of course has to be done underwater but you can still get the hang of the controls.
The "underwater" white balance setting is a happy medium and cannot surpass manual white balance.
The key is to be able to work all the controls fast and efficiently and understand what they accomplish.
DO NOT WAIT UNTIL YOU GO ON A DIVE TRIP TO LEARN THE CAMERA.
