It is an amazing sport, and I am sure you will enjoy it. The best diving I have ever seen was at the coral reefs in Egypt. If you have the opportunity, be sure to go there. Since you're a beginner, a stopwatch online , such as the one at timesles.com, will suffice. It has all the features you need for this type of training. The site offers both a stopwatch online and an online timer. I think this is enough to help you learn how to hold your breath.