Please follow these steps to install and activate your Windows Server 2016 Essentials license:
1. Download Windows Server 2016 Essentials from Microsoft: https://go.microsoft.com/fwlink/p/?LinkID=2195170&clcid=0x409
2. On the page, choose Windows Server 2016 Essentials and download the ISO image.
3. Create a bootable USB or DVD using the ISO and install Windows Server.
4. After setup, open Command Prompt as administrator and run the following command:
slmgr.vbs /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
Replace the X with the license key we sent you.