Your DSL line goes into the external DSL modem and from that into your computers network card. The computer now has the internet. If you want other computers to have connection to that computer and its internet, I would advice you buy a second network card for the machine and connect it that way ignoring the router...
The second card can be wired if you want fast rates or a wireless if you want the mobility. For example, I have a computer which receives the internet via my broadband modem, has a second network card which connects to the hub communicating with another two computers and has a USB wireless adapter to feed my powerbook. The router is mainly for splitting that internet connection directly to several computers.