There are many ways to connect to another Mac on your local network. Here’s one that is one of the easiest.
- Enable Screen Sharing on TARGET Mac. (System Settings / General / Sharing / enable Screen Sharing).
- Find the IP address of the TARGET Mac.
- Enable Screen Sharing on the HOST Mac (Sometimes you have to, and sometimes you don’t).
- Connect to the TARGET Mac. (Finder / Connect to Server / Enter vnc:<IP_ADDRESS_OF_TARGET_MAC>.
- Authenticate. (Enter username and Password of an admin account on target Mac).