Register as a developer, you can register at the following website. https://developers.facebook.com/async/registration+
Log in https://developers.facebook.com/+.
Click 'MY Apps',
Click 'Create APP',
Select 'Business', click 'Next'
Enter 'App Name' and 'Contact email', click 'Create app'.
Page will switch to,
Click Settings>Basic, Copy 'App ID' and 'App secret' here.
Click Dashboard>Facebook Login for Business, click 'Set up'.
Enter URL. URL is https://Domain:9001/api/v1.0/facebook/integration/callback. Domain is your Web Domain.
Click 'Save changes'. And then click Dashboard>Messager, 'Set up'
Click 'Add or Remove Pages' and continue.
Click ‘Create a Page' and complete the page information.
Click Messenger>Settings, 'Add or remove Pages'
Select a page, click 'Continue'.
Click 'Continue'.
Click Messager>Settings>Access Tokens, click 'Generate token'. And copy the token and paste it on the webhook setting.
Click Messager>Settings>Webhooks, Click 'Add Callback URL'.
Enter Callback URL and token. URL is https://Domain:9001/fb/webhook, Domain is your Web Domain.The Token is generated on the previous step.
Click Messenger>Settings, click 'Add subscriptions'
Select all, and click 'Save'.
