How to get a POST request in PHP using curl

I need to invoke this website ...

... selecting "101 - BELLUNO" as ULSS parameter and the string "PIEVE" in the "Nome Presidio Pronto Soccorso" text field as show in the picture belove

enter image description here

using curl in a php code in POST mode.

These are the parameters I can see in my browser console

enter image description here

enter image description here

I'm trying to use Poster Mozilla extension to understand how to manage the request parameters but I've some troubles.

Any suggestion / curl - PHP code samples to help me?

Thanks in advance!