As we know that Facebook has reviewed their bot connection policies, and after reviewing it they have removed the Automatic Bot Connection, now if you want to connect your Facebook page with any Bot, you would need to manually performs certain steps. After your connection to Bot, it will be in development mode and only you (Page Admin) would be able to receive messages from Connected Bot, then you will need to submit your app to the Facebook for review, after Facebook review if they accept your Bot then the Bot would be able to answer to each user messages.
Following are the steps to Connect your Facebook page with the Bot manually.
Login on Botsify.com and create a bot by clicking on “Bot for Facebook”
Go to developers.facebook.com
Click on My Apps on the top right and select “Add a New App”
Give the name to your app and click on Create App ID
Now on the Messenger Product from the Product List click on “Set Up” Button
You will be now on the Messenger Product Dashboard. In the Token Generation Section Select your Page, as you select the page, Facebook would ask you to give permission to app for the page and then the Access Token would appear.
Copy the Access Token and paste it on Botsify
After having Access Token you would need to setup Webhooks. To set up webhooks click on the “Setup Webhooks” button in the Webhook section of page
Now copy the “Webhook URL” and “Secret Key” from Botsify and paste it on the Callback URL and Verify token fields. And also check on the first 3 subscription fields and click on “Verify and Save” button.
Remember that only you would be able to receive messages from Bot, to make it public you would need to submit your app to Facebook for the review. And if they accept your app then Bot would be able to answer each user.