First of all, make sure that each machine's software Firewall allows free local traffic, and that the Firewalls are adjusted to your Network IP numbers. Run the Network Setup Wizard to make all files and a network drive fully accessible.
Then, there are 2 ways:
1. Link Removed - Invalid URL
2. Enable Public folder sharing, all of the folders within it will be automatically shared. Move or copy the file or folder you want to share on the network to the Public folder.