Yes, today it's much harder to transfer files in a local network without using cloud (or external coordinator), for some reason.
of course security was near nonexistent, but it was home LAN, and convenience trumped all.
Nowadays I have NO idea if I could do a similar setup with Windows 10 without resorting to the cloud
Make the PC see each other in the LAN is just a matter of ticking one box. I typically create a folder somewhere and give r/w access to everyone then I proceed to log in with the credentials of the computer then put whatever I want. After I am finished I delete the folder. I think it uses SMB under the hood.