Okay, I found an older post that has some instructions, but I'm getting an error.
I've added:
<link rel="stylesheet" type="text/css" href="http://domain.com/wp-content/plugins/contactforms/styling/cforms.css" />
<script type="text/javascript" src="http://domain.com/wp-content/plugins/contactforms/js/cforms.js"></script>
<?php require('./wp-blog-header.php'); ?>
to the header of the html page and added:
<?php
insert_cform('2') ;
?>
To the body of the page.
The form submits, and the email is sent, but I get the following error dsiplayed at the top of the page:
Warning: Cannot modify header information - headers already sent by
(output started at /home/......../form.php:9) in
/home/........./wp-content/plugins/dd-formmailer/dd-formmailer.php
on line 21