If the computer whizzes explained anything to you about HTML coding for web pages, or to me for that matter, our heads would all be spinning, so I am going to try to explain it from the point of view of someone who has learned to use it, to a degree.
For me, I had to go back to the days when a computer took up a whole building on college campuses and the computer guys carried around these punch cards. Back then, although I had no idea what it was about I did know that each card stood for a command. You had to break down each and every step. My friends would have a whole stack of cards and it would do one thing, in about three seconds. If you messed up and skipped a step, or got them in the wrong order, it would not work. Computers are machines, and can only do what humans tell them.
Computers have gotten much smaller since then, smaller than any of those guys would have ever thought, but the underlying principle is still the same. Computers can only do what humans tell it to do. Now, they have streamlined some of the steps, figured out programming tools to crunch a bunch of steps into one, but you still need to tell it what to do.
HTML coding for web page use are things that tell the computer program what to do. You have a start code with and a stop code. So if you want to make text in italic, or bold you use the start and stop codes for that. There are codes to make a list, codes for page breaks and codes to put links in. All you need to do is keep an HTML codes list next to you and you will know which code to put where.
There are some complicated HTML codes, but lucky for us most of them have been automated, so the everyday user does not have to know when to put a? or, "or,> or,: //, each of which has a specific purpose. Other people do them, and are part of the things that come with the software. What you end up doing is getting the code form one place or another, and cut and pasting it into your website. for instance if you want to track how many visitors visit your site. you go to a tracking site, give then your URL, they make the code for you, you copy it and put it in your site. Other humans create the complicated codes, you just learn how to use them.
The bottom line is that HTML coding for web design are part of the package. Lucky for us, it programmers keep making it easier for us normal people to use. May-be one day we will not have to, and it can all be automated.