There are few ways to do this,
Firstly check that your hosting account enables you to install more than 1 website. If not you might need to buy some more hosting.
Once this is in place, then you should be able to install wordpress using a temporary domain name. Im pretty sure godaddy enables you to do this.
Here’s a tutorial on how then to get the proper domain name working http://jamiemarsland.wpengine.com/2014/05/easiest-way-build-new-wordpress-site-old-site-live/
Hope that all makes sense :)