1. Log into you Primary Site Server as an account that is a member of the Schema Admins security group
2. Copy the SCCM install files to your Primary Site Server
3. Navigate to SC_Configmgr_SCEP_1702\SMSSETUP\BIN\I386 in the SCCM install files.
4. Run extadsch.exe
5. Once the tool completes go to the root of the C drive and review the ExtADSch.log file to verify the schema has been successfully extended.