Nothing

Since its a router , you dont have to worry anything. Just plugin the Ethernet cable to your iBook and to the router...It should be connected...Thats the beauty of Mac

IF anything goes wrong , go to System Prefs > Network.....and see if there is a green light with IP Address....If there is an IP address , then you're set

Are you connecting via Wireless as well ?

In Show , select Bulit-in Ethernet

Make sure to select Configure IPV4 - Via DHCP

and then take a look at proxies make sure that Wrb Proxy is not checked , check for other proxies and just make sure that , they arent checked as well

Then see PPPoE , make sure its not set in PPPoE mode

Thats it

If else fails , select Assist me and it should guide you