Hi @gaetano.picilli,
Kindly refer usecase-2 in the following link which illustrates an example for creating a composite entity:
Also, please go through the following post for better understanding.
https://test-discourse.kore.ai/t/how-to-use-composite-entity/377/4
Let us know if you need any further clarification on the above.
Regards,
Yoga Ramya.