What way to learn HTML?

The only way to learn HTML is to actually write HTML.
Endless videos on YouTube won't make you a programmer or a proficient HTML writer.

In order to learn HTML, you need to write HTML.

That is why in every programming challenge you do in the IGCSE HTML course, you should type it out. You might say this is a waste, but believe me, only through typing do you become a proficient HTML writer.

Think of it like this; does a piano player only copy the notes onto a music sheet, or does the piano player actually play the notes. Only through hours of practice of playing on a piano, does the piano player before proficient. No difference for the HTML writer.