personal trainer is the best way to go..
you may think you can swim, but the real technique is quite hard to master without a close supervision..

i got my lesson at about rm300 for 8 lessons(forgot exactly)
can do frog, freestyle and float

it will come naturally bro..just dont panic..thats the key

set your legs wide apart, kicking alternately, with hands for both staying afloat and balance..

unless your legs have a very good stamina, your head wont able to stay afloat 100% of the time..
just make sure can give a good thrust (with both hands and legs) when you need to breathe in
the air in your lung also helps..