How do I set up a wired router to the internet?

my dad just got an old laptom and we want to use the same dsl connection (bellsouth) for both the laptop and the desktop. I currently use a westell for my desktop and I am with bellsouth. I found a linksys in the closet and I want to use it. I have all the wires. I just need the proccess so that both computers work. I used to know how to do it such as puting the ip address in the address bar and setting up everything. Can you please help me?