I am trying to set up a wireless network at home. Internet is delivered via a USB cable modem.
What I am trying to do is connect wireless access point through ethernet connection on the same computer i.e. internet in is a USB connection, then I have an onboard ethernet socket which is connected to the WAN of the access point. However I do not get available wireless networks. What am I doing wrong? I assume it could be IP/gateway/subnet addresses, if so how to set them correctly?

Thank you!

Try this setup

internet connection sharing from the main computer ( which gets internet from usb modem and has ethernet connected to Access point)works by setting the computer up as a DHCP server and assigning IP addresses and default gateways to all computers in the network,
to configure the gateway computer
go to network connections and go to properties then advanced and enable
'allow other computers to connect through this Internet connection'.
In this case the wireless access point acts as a switch,and the gateway computer will act as a router .
now configure wireless access point as if it is connected to a router.

Note:- disable DHCP on your wireless access point