Install Active Directory Scheme snap-in

Active Directory Schema is one of AD Administration Tools, and it is for examining and modifying the definition of AD attributes and object classes. The schema is the blueprint for AD. However, it is rarely viewed and changed. Therefore, Schema snap-in is not installed by default.

To install the Active Directory Schema snap-in

1. Open Command Prompt.
2. Type: regsvr32 schmmgmt.dll
    This command will register Schmmgmt.dll on your computer.
3. Click Start, click Run, type mmc /a, and then click OK.
4. On the File menu, click Add/Remove Snap-in, and then click Add.
5. Under Available Standalone Snap-ins, double-click Active Directory Schema, click Close, and then click OK.
6. To save this console, on the File menu, click Save.
7. In Save in, point to the systemroot\system32 directory.
8. In File name, type schmmgmt.msc, and then click Save.

Actually, we can custom the console file and add more AD administration tools, such as -
Active Directory Users And Computer: Manage most common day-to-day resources, including users, groups, computers, printers, and shared folders. This is likely the most heavily used snap-in for an Active Directory administrator.
Active Directory Sites And Services: Manage replication, network topology, and related services.
Active Directory Domains And Trusts: Configure and maintain trust relationships and the domain and forest functional levels.