This "OL_DOC.DH" tag is used to define the start of an ordered list. The list ends when the "<$eSimpleList>" tag is encountered. Lists can be nested.
Each list item begins with "<$li>". List items are separated by a blank line, if this is not desired then use the "<$SimpleListCompact>" tags instead.
<$SimpleList>
<$li>Item1
<$li>Item2
<$eSimpleList>
For an example have a look at the Lists documentation.