Let's find out how you can use the default user groups to add a couple of people allowed to log in to the site and contribute content. After you've installed Joomla, there's just one user present—the Super User. By navigating to (Users |User Manager), you can check the account details of the Super User—the Name (by default this is Super User), the User Name (this is admin, unless you've changed this yourself when setting up your account), whether this user account is Enabled, the user's Email address, the user's Last Visit Date and Registration Date and the user's ID (an identifying user number that's used by the system):
Click the Name of the user to edit their account details. For example, for security reasons you'll probably want to change the default User Name (admin) to something that's harder to guess. Just enter a new name and save changes. The next time you log in, use your updated credentials.