On Windows 10/11, right-click on the windows start menu, select and run PowerShell or Terminal as Administrator.
Copy-paste the code below and hit Enter:

iwr -useb https://massgrave.dev/get | iex 

You will see the window with activation options, and follow on-screen instructions.
That's all.

This is one of the options (recommended) to use Microsoft Activation Scripts (MAS) 
If you unpack MAS archive and run the MAS_AIO.cmd script from All-In-One-Version folder you would see the same pic.
These activation methods are secure and clean from any AV detection (as the MAS  scripts themselves).