There are many ways to skin a cat my friend. Please be a little more specific as to your requirements. A starter for 10 is:
int s0/0
description Link to ISP Router at 192.168.254.1
ip address 192.168.254.2 255.255.255.252
bandwidth 64
clock rate 64000
encapsulation ppp
ip route 0.0.0.0 0.0.0.0 192.168.254.1
This will set up your interface and provides a default route to your ISP router.
Please rate if helpful.