Enter a URL for a webhook, enter a Verify Token and select message_deliveries, messages, messaging_optins, and messaging_postbacks under Subscription Fields.Important: you have to replace <'token'> for your real token!
You have to press Add in order to add a Facebook channel. After this you will see this dialog with has two fields, the name and the token. In the field name you can put whatever you want a call your bot. In the token field you have to put the token that BotFather gived to you in the last step. This is all, You have your first bot ready to use!