Server Manager – the most common way
You have probably noticed (and perhaps been annoyed by it) that when you log into most Windows Server operating systems, there is a tool that likes to automatically open called Server Manager. Most IT professionals close Server Manager with a grunt of frustration and then move on to launching whatever administrative tool they intended to use in the first place, but Server Manager can actually be an incredibly useful hub for managing almost any aspect of the server operating system.
Bar none, the most useful and most commonly visited menu inside Server Manager for me personally is the Tools menu that is listed in small letters in the top-right corner of the screen. You can see it in the following screenshot, right between Manage and View:
Click on Tools, and you will get a drop-down list, seen in the following screenshot, of all kinds of goodies. This list grows or shrinks depending on what roles and features are installed upon the server where you are working. Back in the Server 2003 days, we were always opening up a folder called Administrative Tools and finding the consoles that we wanted from there. While Administrative Tools does still exist in Server 2016, it is harder to find, and it is overall much easier and more efficient to launch the admin tools that you need to use right here from the Tools menu inside Server Manager. Inside this list, you can see Group Policy Management listed.
Clicking on this is one common way of launching the GPMC: