its ok, we are here to help.
On the back of the belkin, you will see some ports. 4 Marked as LAN and 1 Marked as WAN. The WAN (Wide Area Network) port is what is commonly connected to the internet, or in your case, the netgear adsl modem's LAN (Local Area Network) port, as the netgeats WAN port is an rj11 style connector, which you will plug into the adsl splitter on your BT socket.
Hopefully you have an idea of what you are doing, other wise this method will likely cause you a few headaches, while its not hard, it is confusing.