To ensure accurate calendar syncing, you need to provide an iCal link from every website where your property is listed. Once you have these links, go to Properties and select the listing you wish to edit. From there, scroll down on the sidebar menu (beneath your property photo on the left), and click "Calendar Sync."
Each platform has its own process, so here are some links to get you started: Airbnb, Booking, BedandBreakfast, Google, HolidayLettings, Homeaway, iCloud, Tokeet, Tripadvisor, VRBO, & Wix.