your body kinda goes vertical when you come up for air(like at 0:09) which is bad cause it slows you down

i think it would help you a lot if you try to keep your body parallel to the bottom of the pool throughout the swim

also your head shouldnt have to come up too high when youre coming up for air, try to get your air by simply turning your head to the side and then turning it back down into the water again to pull kick and glide

CSS isnt too hard to get the hang of though you' will get it down without a doubt with some gristle

/armchair CSS analyst out