Is one of the ports listed as "Uplink"? This should be connected to the cable modem.
Pick any of the other 2 ports for the individual machines.
Assuming you have Win98? (If you have Win95; upgrade to 98SE, or install up to Dial Up Networking 1.3):
Go into the Network properties (right mouse click Network Neighborhood). Make sure "File and Print Sharing" is listed. If not, select add, dialog box should open. Select Microsoft, then you should see File & print.... on the right. Select this and hit ok. Let the installation occur. Repeat on other computer.
In the Network properties window, select the "identification tab". Assign each computer a different name. Assign each the SAME workgroup.
Now, reboot both. Once you've rebooted. Go to the "My computer", RIGHT mouse click "C drive". You should see "Sharing" select this. Now, you can set it for full share, read only etc...
BTW: This will share your entire Hard Drive. You can do the same for an individual folder instead of "C drive" above.
To test the network, run winipcfg( start->run->"winipcfg.exe" on both machines. Get the ip address for one of the machines. On the other machine, get a dos prompt. Type "ping" ip address for the first machine. Like "Ping 192.174.222.01". If you get a no response, than the network is not correct and you have to manually assign an ip address for each computer (Network properties).
In TCP/IP settings in Network properties for the network card, setup one machine as a specific IP address, rather than obtain automatically. The address for one machine should be like: 192.168.0.1, 192.168.0.2 for the second. Both should be setup to the same gateway: 255.255.255.0.
Where's the printer going to be? Assuming it's attached to one of the machines.....
Printer share: go to Start->Settings->Printers (on the remote computer)
Add Printer select Network, there's a browse feature. If the network setup went ok, you should see the other machine and just select it. It should autofind the type of printer.