Forcing a page name in a URL

wordpress

#1

Not sure the right terminology here…

When a user goes to:
http://www.jbryant.org/library

I need it to resolve to:
http://www.jbryant.org/library/index.php

This is because a WordPress plugin I use only works if the page name is part of the URL.

DreamHost support tells me that I need to do this through my .htaccess file. I have modified .htaccess before and generally know how to edit it, but I need someone to tell me explicitly what I need to add. This is not my area of expertise.

Thank you!

jb