...
In order to connect a new FB page to the Leeloo.ai platform, or reconnect an existing one, you need to:
Follow this link and create your public page: https://www.facebook.com/pages/creation/?ref_type=pages_you_admin
Follow to Settings - Messengers section on the Leeloo platform and click on the "get FB token" button
...
After the click, you will see the screen, as in the screenshot below, where you need to click the "connect Facebook account" button
...