<a href="filename.html">Click me</a>
Relative paths are relative to the location where they reside. For example, if you have a folder in the root of your direction named generalinfo, the link above looks like:
<a href="../filename.html">Click me</a>
<a href="http://www.domain.com/filename.html">Click me</a>
Where the HTTP is the full path to your file.