It can be tough to evaluate the validity of the many online resources available for beginning web designers. For example, many professional designers take issue with some of the older content on https://w3schools.com, which I somewhat agree with. But let's face it, w3schools can be a good quick online reference.
There are many others, such as Codecademy's Make a Website tutorial: https://www.codecademy.com/learn/paths/learn-how-to-build-websites. This one steps you through a series of exercises.
Another good one is Shay Howe's site: https://learn.shayhowe.com/html-css/. These are fine, but the technical approach taken makes it a little harder for a beginner to dive in.
Perhaps the best way to learn is to make some stuff and to use https://codepen.io and https://netlify.com (if you do not know Git, use their drag and drop interface) to host it for free and show it to people, or link it from your social media accounts so that you feel pressure to make it good enough for folks to see it.