I want to use the 7800N as a WiFi service only

[cwog001]

I have a spare Billion 7800N that I want to put at the end of an ethernet cable which is connected to my router (which is directly connected to the FTTC Modem) and which also handles all communications with the ISP. I want to extend the reach of my network and to remove the WiFI transmitter from near my work desk.

I want the 7800N to function only as a Wifi transmitter, it is not to handle any IP allocation as this is handled by the router mentioned above.

How can I get the 7800N to work in this way. I would like it to handle the two SSIDs ie internal users and guest users with no access to the internal machines.

Thanks for any help