The storeadmin is where you will log in to add content to your pages, categories to your catalog and products to your categories. The storeadmin is the main hub of your website.
http://www.yourdomain.com/storeadmin Of course you would replace "yourdomain.com" with your own.
You can find your login information for your storeadmin in the New Account Information email that we sent out when we installed your account. If you no longer have this email, you can login to your Client Area and click on Hello (Your Name) and then Email History.