Click "File Manager" in your cPanel control panel to get started.
1) Copy configuration.php file to make a backup in case you mess up the file when completing step #2 and #3
2) Click on the configuration.php file, then choose "edit"
3) Change...
public $live_site = '';
to...
public $live_site = 'http://redwood.greenhostit.com/~yourusername';
(If your hosting account is located on a different server, please substitute "redwood" above, with the name of your server.)
4) Turn off the SEF rewrites in the configuration.php file.
var $sef = '0';
var $sef_rewrite = '0';
I have set these two to 0 instead of 1, and now the links work. They aren't pretty looking, but they work. This is pretty much the only way the temp URL will function properly.
That's it! Your Joomla site should work now with the temporary URL. After you are finished testing and designing your site, you will want to reverse these changes, and then change the DNS for your domain to
ns1.greenhostit.com
ns2.greenhostit.com