Hi There,
Web design ( to me ) has to do with choosing colors, fonts and layout for the particular client you are building the site for. This would be more "artistic" than technical.
Website building has to do with using HTML, CSS and javascript to actually make the website you have designed.
You can learn the code to use by reading the many books on the subject. You can take a college course in order to have a "structured" way to learn. Either way will take considerable time and effort on your part. But if you like to do that it is very rewarding.
As for the "design" part you can look at many sites to see which colors, fonts and layouts that are used for guidelines for your site.
For instance: black text on a white background is very easy to read but is rather "stark".
Would be suitable for a "newspaper" type of page.
A dark background with light text is not as easy to be read ( but it works OK) but is suitable for certain types of sites. You would not choose it for a "party" website but would be fine for general information.
The main way to become proficient is to study, study, practice, practice and allow the time required.
But you can get started with just a few tags in a very short time. See link below.
Hope this helps,
Al