to be able to do this you can set goals of staying under the water for certain periods of time and after you reach your goals you can set new ones. To swim faster you practice the swimming technique. Make sure your fingers are together and cupped a little bit but not tightly. Stay loose because if you don't you will cramp up. Do not bend your knees when you swim and kick as fast as you can . We practice a thing called Zip Up on my team. When swimming reach your hands out as far as you can like you are reaching for a $100 dollar bill that is just out of your reach. Doing this will improve your skills a lot and you can even do more. Good luck.