Have you read the read_me.htm file included with the contact form solution pack? This explains the basic steps for installing the contact form solution pack.
All of the steps you outlined are pretty solid. Really the only files that can be deleted from the Contact Form Solution pack are the read_me.htm file and the contact_styled.php if you are not using it.
As for creating a new CFS form on your site, you will likely want to change the email address it points to, so create a copy of the WA_Globals file, name it WA_Globals2.php in the new contactus2.php file, change the line:
php:
<?php require_once('WA_Globals/WA_Globals.php');?>
to point to the new globals file:
php:
<?php require_once('WA_Globals/WA_Globals2.php');?>
