Ok Andy, you want to disconnect the usb cable thats currently connecting your modem to the pc.
Connect the ethernet lead from the modem to the new router and from the router to the pc.
What you are proposing to eventually do is correct but its usually easier to set the router up using the ethernet connection first then when thats established you can set up the wi fi and disconnect the ethernet if you wish.
When you connect the router to the modem via ethernet and pc to routher via ethernet you should be able to connect to the internet immediately as the cable modems have the username/password info stored in them, unlike ADSL modems.
You should now be able to enter the routers IP address in the adress bar of your internet browser.
Netgear tend to use the IP 192.168.0.1 or 192.168.1.1 for their routers but the information should have come with the router. Type the IP address in and press enter. This should bring up the log in box which will prompt you for the username and password, enter admin as the user name and password for the password, both in lower case letters.
This should give you access to the wifi part and allow you to set the information up in your laptop. The wifi is usually set as not encrypted by default so for security you need to enable it.
If you dont understand something, or if for some reason it doesnt work, ask again. I wont be here until late in the afternoon but I am sure Rik will be on in the morning to answer anything you may need