You really don't need to understand any web technology: I'll look after all that for you. However, experience tells me some of you will twitch until you have a little knowledge.

This page exists as a file on a computer (server) run by the firm which hosts my web sites.  When you clicked '... for the nervous', your web browser sent a signal to ask the server to send a file called bub_tech.htm.  When this file arrived on your PC, your browser interpreted it, downloaded any required images and then displayed it.

You can view bub_tech.htm: right click on the page then click 'View Page Source'.
Let's take a closer look at line #12:

<div class = "Pos_Titl1"><h1>Easy web sites</h1></div>

What does that mean ? It's really quite simple:

<div class = "Pos_Titl1"></div> means display anything between <div class = "Pos_Titl1">and </div>  as defined by style "Pos_Titl1".

<h1>Easy web sites</h1> means display anything between <h1> and </h1> as defined by style h1 (Heading 1 - of which search engines take much notice).

Those words in blue are the Mark-up part of HyperText Mark-up Language (HTML) which is the most important part of the definition of a page.

On line 6, you'll see reference to another part of the page definition:
<link rel="stylesheet" type="text/css" href="stylblis.css">
This tells your browser that styles like <h1> are defined in a stylesheet called stylblis.css - where .css means Cascading Style Sheet. Using a CSS enabled me to put all style definitions in one place. The advantage is that changing a style in the  CSS will affect every page in the web site that references that style.