I think I have the gist of what you are trying to do, but really, you need to post a lot more information about your individual computers to be properly understood.
1st, it important to get your network running properly, before you think about sharing a connection.
2nd, how is each individual computer going to connect to the Internet? Does each one have it's own modem? If so, is broadband or conventional?
3, are you using a modem to connect to a network card, or via USB or what?
There are so many variables here at the moment, it's almost impossible to offer any practical help.
You have to treat each operation separately. The setting up of the network is one piece of the jigsaw, and the Internet Connection Sharing, an entirely different (all be it related) piece.