Each listing has its own iCal export link. Other apps and calendars can read your listing's bookings from it. The export link is part of a listing's Availability settings, which only Pro listings have.
Find and copy your export link
Go to Settings, then Listings (app.hosttools.com/settings/listings).
Open the listing, then its Settings page.
In the Availability section, open Advanced.
Under Export Calendar, click the copy button next to the link.
Refresh your export link
Refreshing makes a new link and turns the old one off. Do this if you think someone you don't trust has your link.
Follow steps 1 to 3 above.
Under Export Calendar, click the Refresh button (the circular arrow).
Click Save. The old link stops working once you save.
Copy the new link and paste it anywhere you used the old one, such as another booking site, a cleaning app or a personal calendar. Until you do, those places stop getting your bookings.