Adding sub to SmartThings mesh network (Connect Home ET-WV520)

I have a SmartThings hub, currently with two Sub wifi mesh devices (Connect Home ET-WV520)

I would like to add another mesh device of the same type (Connect Home ET-WV520), but the instructions available appear outdated

I don’t see an option to add a sub to the mesh network in my SmartThings mobile app, but I do see the two sub mesh devices listed

I think you would go to Add Device->Samsung->Smart Home Hub. From there you should be able to scan the QR code or Scan Nearby.