The time you spent on the course was certainly not wasted. You still learned the basics, but you can't expect them to cover everything. Technology is always changing, and sometimes it's hard to keep up with all of the technical details. Like many others have mentioned, find and read books that teach you HTML and CSS to start with.
I've always been a firm believer that the best way to learn how to do something is by actually doing the work; you gain the experience and knowledge of what needs to be done. This is how I learned HTML and CSS.
For example, I studied Graphic Design and I never learned any web technologies in school, but I knew that having that knowledge would be extremely beneficial in the long term. So I started doing research, reading up on articles and books, and just got started coding pages. If I got stuck, I'd search for it to see if anyone else has had similar issues, read the responses, tried them out and learned from them.