You are probably viewing the website on your own computer, or you forgot to upload the .htaccess file to your server. Use our step-by-step installation guide to see a working website.
We use a file called ".htaccess" to rewrite URLs. This means that a URL such as example.com/page/ or example.com/page.php will actually redirect to an HTML file. However, you won't be able to see this in your browser. The content will be accessible on the “pretty URL”. This technique is good for SEO'ers who want incoming backlinks to redirect to the original URL.
There are also a surprising number of people who mix up the demo version and the paid version. If you ordered both, then make sure to use the files from the paid version. And yes, that seems really obvious.
Note that a .htaccess file only works on Apache servers. We can translate this file to work on other servers, such as Microsoft IIS or Nginx for a small additional fee. More than 95% of our customers have a hosting account that runs on Apache, so this rarely happens.