Update restore manual in README (#635)

Author: OXERY

README.md

@@ -57,12 +57,14 @@ For more information see [the documentation](https://github.com/zigbee2mqtt/hass
 ## Restoring data from a standalone installation
 
 1. Ensure that both environments are running the same version
+1. Ensure you can [SSH to your Home Assistant OS](https://community.home-assistant.io/t/howto-how-to-access-the-home-assistant-os-host-itself-over-ssh/263352) (NOT to the SSH Addon)
 1. Backup your standalone environment `data` folder (possibly leaving out the `logs/` folder)
-1. Configure your serial port using the HA addon configuration UI
-1. Restore your `data` folder contents into `/usr/share/hassio/homeassistant/zigbee2mqtt`
+1. Start the Zigbee2MQTT HA addon with a non-existing `tty` device, to create the `data` folder
+1. Restore your `data` folder contents into `/mnt/data/supervisor/homeassistant/zigbee2mqtt`, e.g. via `scp -O -P 22222 -i  PATHTOUSEDSSHKEY ./data/* root@hass:/mnt/data/supervisor/homeassistant/zigbee2mqtt/`
+1. Configure your serial port and MQTT settings using the HA addon configuration UI
 1. Edit the `/usr/share/hassio/homeassistant/zigbee2mqtt/configuration.yaml` file:
     - Ensure that the serial port section matches the one configured with the UI
-    - Remove any irrelevant sections from the config (e.g. `mqtt`, `advanced/log_syslog`, `frontend`)
+    - Remove any irrelevant sections from the config (e.g. `mqtt` (if not needed), `advanced/log_syslog`, `frontend`)
 1. Start the add-on
 
 ## Changelog