1. Add an new ui panel type which refer to an ui panle category onto UIHandler.cs
2. Update the uiscenedefault.txt with setting current panel as the original scene's default ui
3. Update the uilayerpanel.txt

1. Create a binder script
2. Create a handler script which is partical class.
3. Make a prefab with the UIHolder component addon, then put it under a Resources folder.

Run the entry.unity and you will see the ui panels made just now.