First open a web browser and im guessing that your router ip will be
http://192.168.1.1/
enter your username and password the defalt for myn was no usr name and password was "admin" browse thru the different pages till you find port foward myn is under applications and gaming hope that helps,
also if ur dsl modem servs as a router as well like my speedstream does you may have difficaltys with port fowarding and it may be easyer to hook a hub up 2 it or hook your server directly to the modem and port foward from the router
Hope that helps some I could be wrong as im not a expert on routers i hate the D@mn things but it lets me have wirless access so.....