HubSpot Deal Property Change to Trigger New Google Calendar Event

Hi. I want a property change in the free version of HubSpot CRM to trigger an automation. The exact trigger is a HubSpot Deal field called “Save to Google Calendar”. The automation will create a new Google Calendar Event that is based on the fields in HubSpot CRM’s “New Deal” form. One of the properties is called “Event Date” and that will correspond with the calendar date in Google Calendar. I think I might know how to set up the Google Calendar part, but not the HubSpot CRM trigger. Can someone break down (step by step) exactly which options to choose to set up the HubSpot CRM trigger in Make? Thank you.