Help with API POST Server Connect API Action (OneSignal)

Hi Guys,
Does anybody could provide me some advices about how to use API Action to do a POST API.
I’m testing OneSignal (with a production account and my own Player ID) - and would like to send a test notification to a specific user (me).
I’m getting nuts, i don’t understand how to set correctly my Server Connect API Action correctly (input, header, schema, and different options).

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