It’s important to “save your progress”.
For some people, taking notes helps.
For most people, applying what you have learned is critical.
Have you applied what you have learned?
For example, can you make a basic heading, followed by a paragraph, followed by a button? Which parts are tricky/challenging for you? Which parts did you need to look up?
The goal here, I believe, is not to perfectly memorize everything. As @JeremyLT and @jwilkins.oboe both say, you may need to look up syntax or steps a number of times before “it sticks” in your brain.
Does any of the advice so far help?
Last thought: It might be that you are pushing yourself too hard, too fast. There is only so much you can memorize in a given day.
Pro-tip: If you want to cram lots and have a chance of memorizing what you cram, consider looking into a program like Anki: https://apps.ankiweb.net/ and here on the freeCodeCamp forums: Best Developer Related Anki Decks?