Note: For the steps below, visualize the button layout of a 2-Gang setup. The four quadrants correspond to: Top-Left (A0), Bottom-Left (A1), Top-Right (B0), and Bottom-Right (B1).
Open the Philips Hue App and navigate to Settings -> Accessories -> Add Accessory.
Select Friends of Hue Switch from the list of device types.
Choose Retrotouch (if listed) or select EnOcean (as they share the core underlying Zigbee kinetic transmitter footprint).
The app will initiate a search scan. Because you triggered the combination in Phase 2, the bridge will discover the module on the network.
In your Home Assistant dashboard, navigate to your Zigbee integration panel (ZHA or Zigbee2MQTT) and click Permit Join / Enable Joining Mode.
Execute the 7-second button pairing combo outlined in Phase 2.
Watch your live logs; your coordinator will intercept the pairing beacon and register a new device entry (often recognized generically as an EnOcean PTM 215Z or Green Power footprint variant device).
Once the pairing interview successfully finishes, use Home Assistant Automations to map any of the four button contact actions to toggle or dim any smart entity in your home.