Each line entered will appear in the Links frame/screen as a "link", preceded by a bullet, a plus or a minus. The plus or minus is used to indicate lines which introduce sub-lists (those whose succeeding lines are prefixed with an additional dot character). On the Links frame/screen the plus/minus characters are hot links which expand/collapse the associated sub-list.
When typing in link lines: each line can have an optional description followed by an optional URL (don't forget the leading tag such as http://). If the line is a sub-entry in a higher-level list, prefix the line with one more dot character than the parent has. See the example above for how this looks.
A line consisting of a single "-" character produces a horizontal rule across the links frame/screen. You can also simply include raw HTML as a link by making sure the line starts with an HTML tag <...>.
Advanced users familiar with HTML may wish to know that a leading "=" can be used to start a line which is included verbatim, without even the surrounding table row/column tags. If you use this, you'll want to include table row/columns tags of your own or end and restart the table environment with </table>...<table> or else the browser may well render your HTML outside the links table.