In general, adding a WAP to a wired network is easy. Just plug in the router/WAP, disable its internal DHCP server (and tell it to use DHCP to get its own IP address), and plug its 'uplink' port into a downstream port on your wired router. Then you should be able to connect to it from the wireless devices and see the rest of the network. It's really no different than daisy-chaining wired routers.