Please follow these steps to install and activate your Windows Server 2019 Essentials license:
1. Download Windows Server 2019 Essentials from Microsoft:
https://www.microsoft.com/en-us/evalcenter/download-windows-server-2019-essentials
2. Select Windows Server 2019 Essentials and download the ISO image.
3. Create a bootable USB or DVD using the ISO file and install Windows Server.
4. After installation, open Command Prompt as administrator and run the following command:
slmgr.vbs /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
Replace the X with the product key we sent to your email.