Most Routers practically install themselves. You just take all the default settings (BTW if have you screwed it up by changing things there is usualy a "Reset to factory defaults" setting which you can use to get the router back to where is should be.
I have no idea how your modem is connected with USB AND Ethernet - it's usually one or the other. However the router will probably need the Ethernet cable. So here is how the installation should look before you start configuring the software. PC - Ethernet cable - router - Ethernet cable - DSL modem - modem cable - microfilter (usually) - wall socket. (Unless you have a purpose installed ADSL wall plate with two sockets - one fr telephone and one for ADSL.
You need to find out one simple thing from your service provider and they will have given you that when you first signed up with them and that is your User ID (plus sometimes a password). If you have lost your user ID then you can do one of two things, pick it up from the settings that you currently use with your ADSL modem or go back and ask your ISP.
Now follow the instructions that came with the router. If you don't understand a setting, leave it alone! e.g. Static IP address is nearly always WRONG. Most routers can detect what the connection settings should be so let it do that.
If you don't understand any of this please repost. Good luck.
Terry
August 2006