A. To import an ADMX file, copy the ADMX and ADML files to the folder C:\Windows\PolicyDefinitions folder on the machine performing the group policy object editing. If you're using a central store, copy the ADMX and ADML files to the folder SYSVOL\\policies\PolicyDefinitions\

(Replace with the correct language, such as EN-US)

Editor's Note: the folder's name has been corrected.

Related Reading:

Check out hundreds more useful Q&As like this in John Savill's FAQ for Windows. Also, watch instructional videos made by John at ITTV.net.