From the offical doc, it says I can right click on bone item then select Ragdoll -> Add to ragdoll. But I can’t find the menu item like that.
Here is mine
I think maybe I don’t add a PhysX Ragdoll compnent to the actor.
So I create a new level, add that actor to scene, then add a PhysX Ragdoll component, finally I found no way to save it as an actor asset that can be used in Animation Editor.