I guess some of it could be done by selecting correct QuickSet profile. I'm not acquainted to those, so I'll describe a bit harder way:
- Download and install utility called winbox on your computer. It's a windows app, but works fine on linux and OS-X under wine as well
- connect to your AP through one of "LAN" ethernet ports and perform reset without default configuration
- at this point the device won't have any configuration and the only way of connecting is using winbox via MAC
- now create a bridge and add all ethernet and wireless interfaces (CLI commands are the following, in winbox the structure is similar):
/interface bridge port
add bridge=bridge interface=ether1
add bridge=bridge interface=ether2
add bridge=bridge interface=ether3
add bridge=bridge interface=ether4
add bridge=bridge interface=ether5
add bridge=bridge interface=wlan1
add bridge=bridge interface=wlan2 # if your device has 2 radios
- add basic IP configuration to bridge to make "normal" management connection possible. You can run DHCP client for auto-configuration from your existing DHCP server, preferrably create a static lease for your AP:
Or you can statically set IP address etc. Just take care to use bridge as interface.
add dhcp-options=hostname,clientid disabled=no interface=bridge
- Configure wireless (security profile identical to your main AP, radio settings, etc.). Use same security profile for both wireless interfaces if your device has two radios.
At this moment the AP should be a transparent L2 bridge between wired and wireless...