I recommend you use the suggestions here to gain access to the windows admx files vs accessing the adm... There are more options inside the admx, the directions for admx are at the bottom of this link.
https://www.poremsky.com/windows/use-group-policy-admx-files-in-windows-7-or-8/
The directions in previous post are for using the adm files.
I never could get the "ADMX" files to load, even after copying them to c:\windows\policydefinitions. the gp editor complains that only ADM files can be used. Interesting.