how to connect20 computer using lan
Much can I explain and there are some additional tools for you to purchase and configure on your PC, such as: HUB, cable & RJ45 connectors.
follow this step to configure your PC
right click on My network places-->right click on Local area network icon-->properties-->internet protocol(tcp/ip)-->click on ip address and assign an IP (like 192.168.0.5 subnet mask 255.255.255.0)
repeat sam with other computer/laptop but put different IP address like one 192.168.0.1 and other 192.168.0.20; subnet mask will remain same.
then connect network adapter to all computers.