You can start uploading files to your websites even if your domain name has not registered yet.
To access the FTP without a domain name enter this into your ftp manager:
67.228.97.92
If you wish to see your website without the domain name we offer a temp URL for you to use. To access the temp URL via your browser:
http://67.228.97.92/~YOUR-USERNAME/
Make sure to replace 'YOUR-USERNAME' with the user name from your control panel. This can be found in your welcome email after your purchase.