yeah get a router. actually to clear up what lostman said, routers are usually a router/ switch/ DHCP server all-in-one with the main features being:
router - used with a routable protocol like TCP/ IP makes it so you can use a wide area network WAN like the internet.
NAT - lets 1 external IP be shared among multiple computers and has inherit security.
switch - unlike a HUB which is a multiport repeater that takes in one signal and repeats it to all of the computers, a switch knows where to send the transmission making it many times more efficient
DHCP - this is what you were talking about when you asked about what numbers you needed to enter. with DHCP all you do is leave everything at default which is "obtain IP address automatically. the DHCP server will automatically assign IP addresses to all devices.
anyways buy a router, plug the broadband modem into the WAN port on the router, and plug all computers into each port 1-4+ and you can share your internet connection and data files