Oh dear networks from scratch!
Try this ther eis a network wizard that can help.
Basically you have to have a connection between the machines (either ethernet cross over direct cable) or (ethernet blind cable through a router or ADSL modem) or via wireless.
Each of these systelm have theor own software and or glitches to confuse you.
right so noext ech machine (and in some cases ISP ADSL modem) hae to have theior own 'private' adresses (starting at 192<168.1.0 and going up by 192.168.1.1 + etc)
Once everythjing has its own unique address and cables all OK and firewalls turned off (or allowing these addresses) you whould be able to use the old DOS commands ( se command prompt) and 'Ping' trhe adresses to elicit a response. the jargon is when you get he msdos command prompt > you then type
ping 192.168.1.1 (or whatever addrss you used for toher computers) and you shud get the repsonse pa