There are a lot of options out there. But, having so many options out there is also a problem. Which is better among them?
I can guide you in the way I learn basic HTML5 & CSS3. I have started learning from Freecodecamp and general assembly. Then I have started making basic projects which are solely based on HTML5 & CSS3. It will be an easy process and you will be confident after building some basic projects. You can get more project ideas from youtube too.