Correct - in AP-Only mode, do not use the WAN (Internet) port on the secondary router. Many routers actually disable this port when you do the reconfiguration to AP-Only mode.
0- First and foremost, reset the router to factory defaults!!
Consult your manual (or Google) for how to do this. Previous customizations can (and likely will) give you hell with this.
1- First, determine what will be a usable LAN IP address and subnet mask for your secondary router. Assuming that your Netgear is still at its default 192.168.0.1/24 config, a "safe" address would be 192.168.0.254, subnet 255.255.255.0; no DNS or default gateway settings will be needed.)
2- disconnect secondary router from network.
3- Connect a PC to said router via hardware. Log in to router.
4- Reconfigure router as follows:
- UPnP disabled
- Set WAN config to Automatic
- Routing (may be termed RIP) disabled
- Set LAN IP address of router. Reload your browser, pointing it at router's new IP address.
- Disable the router's DHCP server.
At this point, shut down the router, connect it to your LAN, and power it back up. Check functionality (can be either via wired or wireless - doesn't matter.)
Work? Shut it down again, and move it to its new home (connected to the PC.)
give that a go, and report back.
(damn, I really need to get that FAQ done..... )