Connecting to other computers?

I have a 2015 iMac on my desk running Sonoma 14.5; a 2015 MacBook Pro on the coffee table running Zorin 17.1 Pro, and a 2011 MacBook Air in the bedroom running Linux Mint. All are connected to the internet by wi-fi through the Verizon Fios router in the front closet of my apartment.

All I want to do right now is open the file manager on any of these computers and browse the hard drives and transfer files from one to another, yet after a week of installing samba and figuring out the difference between a hostname and a domain name, I'm no closer to getting this done. All of the articles I've found on this topic assume I'm wanting to "connect to a server," or "connect to a NAS drive." I don't have either of those; I'm sitting here in my living room.

Can someone point me in the right direction as to what I'm not understanding while trying to figure this out? Kinda frustrated trying to accomplish a task which seems to me should work right out of the box amount all of these new operating systems.

I don't know enough about Macs to offer advice on that one. Firstly, there are some items you may not wish to be available to all computers. Now Mint and Zorin both contain the folders named 'Public' just like that other 'OS'. Items you wish to share should go in there, then right click the 'Public' folder and select Properties. If not on the interface that opens, might be Permissions, but there should be an option to 'Share this folder'. This hopefully should shoe up in your network searches as far as the GNU/Linux machines. One thing is crucial just like in Windows they have to be in the same workgroup.