Use Ethernet to connect two Mac computers
You can use an Ethernet cable to connect two Mac computers to share files or play network games. If your computer doesn’t have an Ethernet port, try using a USB Ethernet Adapter or a Thunderbolt to Gigabit Ethernet Adapter.
Connect a standard Ethernet cable from the Ethernet port on one computer to the Ethernet port on the other. You don’t need to use an Ethernet crossover cable.
On each Mac, choose Apple menu > System Settings, click General in the sidebar, click Sharing on the right, then note the computer name for each computer. (You may need to scroll down.)
In the Finder on one of the Mac computers, choose Go > Connect to Server, then click Browse.
Double-click the other computer in the window, then enter your password, if necessary.
If you manually configured the TCP/IP settings for the Ethernet service on the computer you’re connecting to, you may need to enter that computer’s TCP/IP address in the Connect to Server dialogue.
To see or set the TCP/IP address, choose Apple menu > System Settings, click Network in the sidebar, then select Ethernet in the list. (You may need to scroll down.)