Well, let's see if I can help you with this:
site url = the full url of the site the coupons appear on (
http://www.yoursitegoeshere.com/)
mysql_host = normally simply localhost
Coupons Database = Name assigned to database (assuming you used the Mysql wizard just enter the database name
Database User = This will be the Mysql database user name
password = whatever password you set up for the database
Invalid Page = full url to an error page if the user enters a wrong url or coupon code (you will have to create this page and then simply place the url to it here)
This appears to be a config.php type file, so you would simply do the above, save it and upload to the root of the web site.
Hope this helps.
Dave