Emotions part is very true, it is not easy to keep your emotions in check that quickly, it may take some time to make a profit when the time comes because you are worried or fearing or happy or excited or whatever else. You may make mistakes if you think with your heart and not with your brain, a lot of people make that mistake and that causes them to have a trouble in the future.
It is going to take some time before we can master trading, but if we can master not using our emotions as our first step then the rest will come easier. Sure you need to learn TA, or need to learn how to read a chart, or many other million things, but if you can't control your emotions then all the other stuff means nothing at all.
That is the hardest part to master as well. I know you said we should do that at first, because rest is less important, but learning the rest is easier. For example learning what bollinger band is and what it does and what happens when it is X number or Y number, those are all easy stuff, it takes maybe an hour or two to learn what it is, and surely there are many other things like that so it takes time to learn it all, but you just learned that in a few hours.
Whereas emotions are not like that, to learn how to control it and not let it get to you when you are trading is not something that can be done in a few hours, it is something you try to master for months and that is why it takes a long time to make it happen for a while.