Quite simple, what you want to do is open up help/index.tpl and just add
Code:
{elseif $section eq "other"}
{include file="help/other.tpl"}
Make sure you add this before the {else} tag and after the {if $section eq "Password_Recovery"} tag.
so if some one went to help.php?section=other then it would display other.tpl.
Hope this helps!