Aiglon,
Most modems connect to the PC via a Crossover Cable. With a router, you need to use a standard cable. So you will need 3 cables. (Since you will not be able to use the Crossover Cable provided with the modem.) Connect the cable to the modem in the Uplink Port. The computers will use the other ports.
Then you will need to setup PPPoE in the Router. It is pretty straight forward. (The Router Manual should have step by step directions for setting up the PPPoE.)
Take Care,
Richard