The following is probably the easiest if they are both Windows computers, on the same network (same router).
-Go to the Network and Sharing Center in the control panel on both computers.
-Turn on Network Discovery
-Turn on Public Folder Sharing
To Share a file/folder
Go to your public folders. (Usually C:/Users/Public)
Anything you place in these folders are accessible to the other computer.
To retrieve a shared file/folder
Go to back to Network and Sharing Center
Go to View Computers and Devices
Double-click on the other computer that shows up there
You should be able to view the other computers Public folders.
Let me know if something doesn't make sense or doesn't work!
Creativity.