From the Airbnb website:
Log in to Airbnb
Go to www.airbnb.com and log into your Airbnb account.Go to the Calendar section
On the right-hand side of the Calendar, select the option "Availability settings".
Scroll down until you find the "Connect calendars" section.Connect calendars
Click on "Export calendar".
Copy the link that appears.
From the Check-in Scan website:
Log in to your web dashboard
Access your Check-in Scan account.
Go to the Properties section and click Edit
Navigate to the Properties section and select Edit for the desired property.
Import the iCal calendar
Within the property settings, go to the iCal tab.
Paste the link you copied from Airbnb.
Click on Import iCal.
In a few minutes, your Airbnb reservations will start syncing in the Bookings tab.