We need to note that the originating poster is a 16 year old boy. Stick to a handsaw, please.
He is old enough to drive a car which is a lot more dangerous than a chainsaw
There is something to that, but.... you have to be trained to drive a car, pass a test to prove that you are proficient. I’ve been thinking and cannot remember my age when I started using a chainsaw bucking firewood, was young enough that pumping the bar oil with my thumb was difficult ( the saws we had did not have auto oilers) . Was probably early teens when I started felling trees. I don’t remember well the one on one instruction I received, as I believe it came in tif bits here and there and the learning was natural. Most kids now are not growing up the way I did, and the work that came natural to me and the caution and awareness that goes along with it is not there. You cannot learn to use a saw proficiently and safely to fell trees from a video. There are countless variables that only experience can teach. One on one teaching is also difficult as it is hard to hear over a screaming saw, and being close to the operator can be a dangerous situation. There is good advice given here and bad, good instruction and bad. Some is regurgitated, some is just the way people do it not knowing there is a better or safer way. Lots of ways to skin a cat, and people develop their own way of doing things and that becomes the right way for them. People with thousands of man hours on a saw regularly have life changing or ending accidents that are a result of complacency and doing the things that has always worked for them.
My advice to you, start cutting 4” or smaller diameter trees with a hand saw and axe Read the lean of the tree and slope of the land it’s on. Pay attention to the soundness of the tree, a tree that you think is sound but is rotten inside can make for a bad day, it is unpredictable. I do not cut a 4 inch diameter tree the same way I do a larger diameter tree, but for learning purposes it would be good for you to wedge cut and back cut as if it was a large tree and learn how the timber reacts in different situations. Look up how to make a proper wedge cut and back cut. Should be videos on it, try to find a video from a saw mfg or other professional source. There is more to it than hacking out the wedge and making the cuts meet. Do not cut when it’s windy, this is your hobby and you don’t have to cut in those conditions, so don’t.
Be careful.