Networking setup: add a link to manual way (#641)

Author: igorpecovnik

tools/include/markdown/BNS001-footer.md

@@ -29,3 +29,5 @@ Choose between:
 - Review and confirm your settings.
 - The system will apply the configurations.
 - Your network connection should then be fully established.
+
+If you experience issues or prefer full control, follow the [manual networking setup guide](https://docs.armbian.com/User-Guide_Networking/).