Wifi VPN AP for 2nd router

Installing and Using OpenWrt Network and Wireless Configuration
1

I would like to add another wifi network to access easily NordVPN services if needed. Every device shall be routed through VPN when they are connected to 2nd router. How to setup the second router? I tried to add it as a dumb access point but that didn't work.

2

First create the SSID and network. An example from the wiki with the guest interface.
Set up the VPN on the device, if you don't have already.
Create the appropriate policy routing rules and routes to forward traffic from the new interface via the VPN.