Get the link to your Booking Engine from Property Settings / Booking Engine / Your Engine Link and copy it.
Open your Facebook page, Home section.
Move the cursor over the button which appears on the top and select the Edit Button option.
Select the button type - Book Now button.
Then, click on Next.
Select how the button should work - in this case, select Link to Website option.
Paste the link to your Booking Engine, and Save it.
Check if everything is correct and click on Finish button.
That's all. Now the guests can book easily from your Facebook page!