Creating a network in between 2 or more instances

Hi Team For my learning purpose I have a plan to create a network in between 2 running instances ex sys 1 and sys 2. Sys 1 is a Server (AMI Wndows server 2019) and Sys 2 (AMI Wndows server 2019) is client, I need to create a network in between Server and Client, which Main Domain and Child Domain or Tree . I need to bring the sys2 ie client as a Child Domain and create a AD user and group policy etc.