Help with P98ORCH

I was trying to use P98ORCH to test launch one orchestration that does not require any input and I'm getting the error message below:

{"message":"Input JSON is empty. Request must contain a JSON string.","exception":"com.peoplesoft.e1.bsfn.b98ORCH.CallOrchestrationNotification$CallOrchestrationNotificationException: Input JSON is empty. Request must contain a JSON string.","timeStamp":"2020-10-26:23:05:06.914"}

Is there any manual on how to use P98ORCH?

If my orchestration does not require any input, what do I need to fill in P98ORCH to make it call the orchestration?

Thanks

Nicolas