There are three kinds of lists you can make in HTML: unordered, ordered and description (formerly called "definition").
An unordered list displays bullets to mark each list item:
An ordered list numbers the items for you:
A description list allows you to organize information in a "term/definition"-type format, but it can be used to organize any listing of information where each unit comes in two parts:
All types of lists do their own indenting automatically for you!
The coding for lists requires a conveniently mnemonic paired set of tags at the beginning and end of the list which identify its type:
<ul></ul> for an unordered list
<ol></ol> for an ordered list
<dl></dl> for a description list
Then, within the lists, each list item in an unordered and ordered list is enclosed in list item tags: <li></li> (In "old" HTML this tag didn't need a closing pair, and current browsers still support this usage. Current standards, however, require that all tags be closed.)
For a description list, the term part of the item is enclosed by this tag: <dt></dt> and the definition part by this: <dd></dd>.
So the coding for my unordered list above is:
<ul>
<li> Item 1</li>
<li> Item 2</li>
<li> Item 3</li>
</ul>
For the ordered list:
<ol>
<li> Item 1</li>
<li> Item 2</li>
<li> Item 3</li>
</ol>
And for the description list:
<dl>
<dt>Spain</dt>
<dd>2010 World Cup winner</dd>
<dt>Italy</dt>
<dd>2006 World Cup winner</dd>
</dl>
You can make the numbers in ordered lists and the bullets in unordered lists conform to different styles if you want. Just add a style attribute to the <ol> or <ul> tag.
Ordered lists don't have to be numbered 1-2-3.
You can use a style attribute to change them to letters, Roman numerals, and even Greek letters! (See the list of possibilities here.)
To make your ordering A-B-C, type this: <ol style="list-style-type:upper-alpha">
You can even make the first number something other than 1, A or I, by adding the attribute start= and giving it another value. For example: <ol style="list-style-type:upper-roman" start="II">.
Non-standard, but still widely-accepted HTML changes ordered list types with a type attribute. For example, you might see <ol type="I"> to make a Roman numeral list or<ol type="A"> for capital letters.
With <ul>'s you can really get customized!
First, you can specify another shape, other than the filled-in-circle bullet that's the default, for your bullets.
<ul style="list-style-type:circle"> makes the bullets open circles and <ul style="list-style-type:square"> makes them squares.
You can even have no bullet, just an indented listing of items, by saying <ul style="list-style-type:none">. This would make a list like this:
Spurs championships (so far):
For even more customization (any small image can be a bullet!) see the Styles Usage tab.
To make a horizontal navigation area (like I did for this guide) you add a style statement with the display:inline value to either your list tag (and it would normally be an unordered list) or your list item <li> tags.
For more details on making these attractive tab-like features, check out this page from W3Schools. You can even get some free software that will help you generate a variety of these tab sets; just google "tab generators."
The cute little train graphic line on this page came from Realm Graphics, a nice free graphics site.