You already know a little bit about ADMX and ADML files – that they are used when new settings need to make their way into the Administrative Templates section of the Group Policy Editor. Now, we need to figure out how to actually use them in our environment.
There are a few different reasons that you may need to work with ADMX files to modify your templates. One is when making Group-Policy-management platform changes. Each new Windows operating system that releases comes with some new settings and functionality inside of Group Policy. For example, the GPMC inside Server 2016 has more capabilities than a GPMC running on Server 2012 R2. If you would rather continue using your Server 2012R2 for GPMC management duties, rather than spinning up a Server 2016 (or Windows 10 client) for this purpose, you could grab the ADMX files from a Server 2016 and copy them over to receive the new functionality. Another reason to become familiar with using ADMX files is that software vendors (including Microsoft) will sometimes release customized ADMX/ADML files for administrators to use in order to modify and interact with some of their software offerings. Third, you may need to create your own template settings in order to customize homegrown applications.
Whatever your reasoning for using ADMX files, let's work together to put some into place so that you are familiar with the process.