One of the PCs needs to be hardwired to the router, using the cable that Belkin provide, so it would be preferable to temporarily use the PC that will be physically nearest once configured.

Once the CAT cable is plugged in, open Internet Explorer or other internet browser, and ensure that the Address bar is visible (make sure there is a checkmark in View | Toolbars | Address bar)

In the address bar, type in the following:

http://192.168.2.1

and press enter

Insert the necessary details for accessing the internet into the browser window that appears. Once done, get them to consider implementing WPA-TKIP for security