You need to supply more information. What number do you need to call on the ISDN ? What IP network are you trying to connect to over the ISDN ? If this question is genuine (and not your CCNA homework) , then please provide some additional information, and we can help you further. It also depends on where you are in the world, so please indicte which country you are trying to configure this router.
For a static route use the command
<b>IP ROUTE x.x.x.x y.y.y.y z.z.z.z </b>
where x.x.x.x is the destination network, y.y.y.y is the subnet mask and z.z.z.z is th egateway address.