Very stylish site. The contact form won't work because the "action" setting of the form is blank:
<form action="" id="contacts-form" method="post">
You need to set up a file on the server, written in PHP, to process the input. This can be the contact page itself. In which case it has to be called "...ContactUs.php". You need to learn how to retrieve post variables and process them into an email which is sent to your email account. It is fairly straight-forwards, but is a separate language from HTML and CSS, that you need to learn.
By the way, it is better not to use spaces in file names. Use hyphens "-" or underscores "_" instead, or just capitalisation e.g. "ContactUs.php".