Open Roblox Studion: open it and follow this steps below Import a R15 rig to your workspace and anchor it and use Blender rig Exporter, which I provided at Prerequisites (Install this plugin in Roblox ...

It seems easiest to start with Method 1. Of course making this work also requires (a) extending the Asset Handling and Editor Studio to support Morph Targets, (b) supporting animations of Morph ...