In order to allow your visitors to login with their Facebook account, first you must create a Facebook App. The following guide will help you through the Facebook App creation process. After you have created your Facebook App, head over to “Settings” and configure the given “App ID” and “App secret” according to your Facebook App. Let’s Learn…
From the product list page click on Set Up button from “Facebook Login” product.
When you’re done click Save Changes button.
When everything is done, Switch to “In Development” from the top. It will make your app public.