try to swim

The ideal would be to take a quick swimming course, a few lessons with a professional will help you gain confidence and to know what to do if something goes wrong. Then practice, first in the shallows and then slowly move into deeper water until you are comfortable being in deeper water. The ideal would be to swim somewhere where there is a permanent life guard just in case you feel uncomfortable you can always ask for help. The thing is the more you swim the better your muscles and breathing become, so in that way you become a better and stronger swimmer.

You should exercise swimming and floating on the shallow water first. Try float on the water in "arrow" position and than kick with the legs. You can use a board to help you floating