Linking reservation calendar on WP with booking

Hello, I have a website and I am using pinpoint reservation system installed and would like to link our booking calendar with booking.com calendar.
It’s clearely stated in booking.com that i should Copy + Paste the API from our website to booking.com but i couldn’t find the API in our website

does anyone please know how to do this?
Notice please that I am a beginner with wordpress.

The page I need help with: [log in to see the link]