Edit the PHP variables at the top of contact_engine.php to match your email information.

DO NOT change the names of the files.  The contact form will submit to the contact engine,
which will then transfer to the thanks and error pages.  If you change the names of the files
the transfers will break.

The Telephone field is Optional (won't get error page if not filled out.)
You can remove it from the form, but if you leave it you should mark it as optional.