Khan Academy's HTML courses are not very indepth. Once you finish all of them, you will have learned a lot but nowhere near your full potential. You should have garnered enough knowledge to make at least a half-complete something, but that may not be enough.

If you're confused on something, then try googling it. Helpful answers often come from websites like w3schools and Stack Overflow. You can also go below your program and request help.

Thanks for your comment! I will keep that in my mind.