This is a short HTML example, aimed at helping newcomers.
     HTML commands are called tags, and are derived from the commands used by large printing presses.
     A good book to learn from is "Teach Yourself Web Publishing with HTML 4 in 21 Days", published by Sams. ISBN 0-672-31345-6. Author Laura LeMay has a real knack for explaining things. Fret ye not, I'm not in the royalty stream, but it is refreshing to find a well written anything.
     By definition, no one becomes an expert in anything in 21 days. Thus, here is an excellent book with a silly title. Beats the reverse!

This line uses the largest font, h1.

This line uses the smallest font, h6.

      This text uses the h3 font size. This is typical text, good for covering your topic. This vanilla text has no HTML code for paragraphs or line breaks. The browser wraps the text from one line to the next. Look at the HTML text and notice that line breaks in the file do not match the line breaks in the display. Actually, line breaks in HTML files are meaningless, and this is just an example of that. Layout is done with HTML commands, not the appearance of the file. Thus, HTML is NOT WYSIWYG (What You See Is What you Get).
      One gets WYSIWYG from word processors, but not on web pages.

Below is a full width ruler line, default narrow thickness.

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Below is a full width ruler line, but thicker

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The next ruler line is the same size, but blackened

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The next ruler line is centered & narrowed.

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The next ruler line is red, centered & narrowed.

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The next ruler line is on the left

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The next ruler line is on the right

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Using ordered lists to create outline style of presentation.

1. 1st category Line
2. 2nd category Line
   1. This line is subordinate to the 2nd category line.
3. 3rd category Line
   1. This line is subordinate to the 3rd category line.
      1. This line is subordinate to line III,1.
4. 4th category Line
   1. This line is subordinate to the 4th category line.
      1. This line is subordinate to line IV,1.
         1. This line is subordinate to line IV,1,A.
            1. This line is subordinate to line IV,1,A,1.

Hope this helps you learn.                              Neal