Until a domain name is purchased and fully propagated, users can view their websites by using either a browser plugin or by editing their hosts file directly on their computer.
Editing your hosts file is a temporary measure to preview your site as it will load from your HostGator server. This lets you make changes on a server other than the one loaded by your domain when visitors access your page. When finished you will want to undo the changes you have made to your hosts file.
This is very useful for development purposes, as you can work on your site on an alternate server using a hosts file while visitors may still visit and use your existing site.
How Do I Edit My Hosts File?
The following article will provide detailed instructions for how to modify your hosts file either through browser plugins or through editing system files: