@Luca-Coraggio, the "TRIGGERcmd Smart Home" Alexa skill is the one you want. Do you have a device for each command listed in your device list in your Alexa app? You'll need that because that's what you're telling Alexa to turn on/off. Please try changing your voice word for the Steam command to just "steam" so you can say, "Alexa, turn on steam", or in your case (Italian), "Alexa, avvia steam".

@Hannibal I see an error in the json. There should be a quote (") at the beginning of the word background.