USDz import from fusion-360 (cant create joints between different parts of a robot body))

Hi, I am new to Isaac Sim and import the robot USDz file from fusion-360. When I try to create the joints between the robot body(chassis) and wheels, I got the following errors.
Could anyone please help me. ( A video solution or detailed solution is really appreciated.

Thank you…

2023-05-29 19:45:52 [Error] [omni.physx.plugin] PhysicsUSD: CreateJoint - you cannot create a joint between a body and itself (both joint bodies must be unique) for joint prim: /cypher_base/rear_right_caster_joint

Hello! The errors are pointing that the Joint’s Body0 and Body1 are the same - Can you select the /cypher_base/rear_right_caster_joint and check in the Properties if the connecting bodies are the same or different?

Additionally - Joints must be created between Rigid bodies, so you need to ensure that whatever is on Body0 and Body1 have the RigidBodyAPI associated with it (in the properties panel it will have a Rigid Body section).

Rigid bodies cannot be nested, but it seems to me you already have that sorted out.