Unsure how to use the Key field in Webhook

I have an URL that returns JSON, however I don’t know what to use as the Key. The data looks like this:

{
 "drinkName": "Bacardi Special",
 "glass": "Martini glass",
 "glass_url": "https://xxxxxxxxxxxxxx",
 "directions": "SHAKE all ingredients with ice and fine strain into chilled glass.",
 "measure": [
  {
   "amount": "1 1/2 fl oz",
   "selection3": "Bacardi Carta Blanca light rum"
  },
  {
   "amount": "3/4 fl oz",
   "selection3": "Rutte Dry Gin"
  },
  {
   "amount": "1/2 fl oz",
   "selection3": "Lime juice (freshly squeezed)"
  },
  {
   "amount": "1/4 fl oz",
   "selection3": "Giffard Grenadine Syrup"
  },
  {
   "amount": "1/6 fl oz",
   "selection3": "Giffard Sugar Cane Syrup"
  },
  {
   "amount": "1/3 fl oz",
   "selection3": "Chilled water (omit if using wet ice)"
  }
 ],
 "image": "https://xxxxxxx/contrib/stock-images/2016/x/xx/xxxxxxxxxxxxxxxxxxxx.jpg"
}

I am a complete rookie when it comes to webhooks so looking for some guidance.

Thanks.