Securing your store
Before you make your store publicly available to the world, you do have to recognize that there are bad people intent on accessing your store's backend without authorization. Using Chapter 9, Security and Administration, as a guide, you should work with your Magento developer to install security according to best practices.
System | User Roles
Start by creating the various roles needed to operate your store. Use the list in Chapter 9, Security and Administration, as a starting point.
System | All Users
With your roles established, you can begin adding your users.
Note
It deserves repeating: create user accounts for each person who will access your backend. Never share credentials among users.