OpenWrt Bridged AP

Hi, I am trying to configure OpenWrt in bridged AP mode. The router with OpenWrt will accept internet from it's WAN port(connected to a non wireless router) and relay the traffic to its LAN ports & Wireless. How do I achieve this configuration? I am also using PUTTY via SSH.

This guide uses LAN port for internet input. I wanted to have internet coming through WAN port of the wireless router from Ethernet port of my cable modem (non wireless)

A bridged AP has the input and output on the same network. It does not route or firewall anything thus the name "dumb AP".

If that is what you want you can make WAN a bridge and attach a new AP to it, or bring the wan physical port into the lan network and not have a wan network at all.

I just simply edit the switch, configuring the WAN port to be the same as the other 4 LAN ports.