Managing a User Account's Rights: Adding a User to a Group
Solution 1
To access an account, on the Taskbar on the server, click Start -> Administrative Tools -> Active Directory Users and Computers.
In the left frame, expand the domain and click Users.
In the right frame, double-click the user name or right-click it and click Properties. Click Member Of:
Click Add... In the bottom text box, you can type just the beginning of the name of a group:
Click Check Names:
Click OK. Click OK.
Solution 2
In the right frame, double-click Domain Admins or right-click it and click Properties. Click Members:
Click Add...
In the bottom text box, you can type just the username of a user:
Click OK:
Click OK.