First time swim freestyle

After watching a youtube video that betrand showed me, i gained much inspiration to try out freestyle. So betrand and i practice swimming in the pool and we have a little competition of freestyle..

So we teach each other what we know about freestyle.. and we try and try and try... Freestyle is a very tiring stroke to use but if used wisely, you can swim so much faster than breaststroke...

I know a bit of how to use freestyle but the execution of it is extremely exhausting... And i cannot understand why the people in the video are swimming

I think that breaststroke are for girls because of the word breast. I don't have breasts, therefore i will use freestyler!!!

some tips i gathered...
- Lock your arms 90 degrees when you execute your strokes
-breathe while you lift up your hands for the stroke.
-body must maintain close to the surface

pls add more tips!!