Contact us form will not work unless you have your files running on a hosting server with PHP / JS. When you have your files ready on your hosting server, you need to edit the settings to make the email function work.
Open /mail.php and change your Receiver Email Address at the top from firstname.lastname@example.org to your real email address. Also replace yourdomain.com with your real domain name in logo image url in the email body template.
Please feel free to contact us in case if your email feature does not work because some server settings do not allow normal PHP email function.