To make things easy, the Mac screen being shared will be called the “server” and the other Mac connecting to it will be called the “client”. We’ll break this walkthrough into two parts, one for setting up the “server” and one for connecting to those servers with a “client”.
With sharing enabled on the server Mac, now a connection can be made from the client Mac (or PC).
You can also directly access and use the Mac VNC client Screen Sharing for this purpose.
The client Mac will now connect to the server and you’ll quickly find the servers screen sitting in a window. Anything left open from the user you logged in as will be visible, and you have full access to everything on the Mac. With fast enough internet connections, there isn’t much lag in using the remote Mac at all, though it’ll likely be smoothest if connected over a LAN.