Take it slow, and learn by practice.
Don't skip steps, because you will never know how usefull can be something, even if it is harder to understand.
to put things into perspective, if you were to group all three languages as a whole, html would be about 5%, css would be 30% and js would be 65%. learning basics imperative js i.e. if, for, while, do, switch break; is pretty straight forward and is pretty much the same across most C based languages. After that you’ll need to learn event driven, object oriented and functioal js, which will take a bit more time.
But there is no rush, just take it one stage at a time.