Cable Modem Install

I have Win XP and have 3 pcs on local network. Im getting cable modem and SMC router with 4 ports. My ISP uses dynamic IP addressing. Currently cliens use static Address, Do Change my clients to use DHCP.. Also do I set up dhcp range. Also Please suggest any tips. I assume I will be connecting cable modem to router.. aLSO hOW DO i SHARE CABLE MODEM wTN