Sara

First of all, you said "routers", do you mean yo have more than one?
Your router has one "external" or "internet" port, and one or more "internal" or "network" or "LAN" ports. If you have wireless it is "internal" too.
Your Internet modem should connect to the "external" port only.
The computers and other home devices go to the internal LAN ports. If you have a separate hub/switch they are connected to, the switch itself should connect to the "internal"
If it doesn't run by default you'll have to follow the Quickstart instructions given with your router.
Note: if you have wireless, you SHOULD setup your router as per instructions, because by default anyone close to your router can connect to it.