I installed my first network recently - worried but it was simplicity itself. However, you need LAn connection on all PC's - apparently USB doesn't work. Attach the first PC to BB via the router and follw the instructtions provided with the hardware. You will have to use the router to log onto a special http in order to set it up, but first read the instructions to see what information you need and get this from your ISP. Once you've got the first PC installed, just connect the second via a straight LAN cable and it should work immediately.
Warning - first time I installed, I use a cross-over cable by mistake. I then thought all I need to do was attach the correct cable. Wrong. You then need to uninstall your LAN (on the second PC) and reinstall it with the correct cable connection.
You can tell if your connections are working - on the router each will have light which should hold steady until you transmit at which time it will flash; similarly, on each PC there will be one or more lights where the cable connects.