Can someone please help me. I'm a complete noob when it comes to networking, and the manual is only confusing me.

I have no idea what I'm doing.

I have a Dynalink RTA-1320 modem/router, and a D-Link DIR-655. I want to set them up so that the RTA-1320 is acting as modem ONLY (bridge mode?), and the DIR-655 is doing all the routing.

How do I set up the RTA-1320 to be modem only?