Regarding Facebook, you need to add the “App ID” code that you can obtain creating a new application on Facebook developers. Login with your account and click on the Add new app entry.
Fill in the form with the required information.
If the creation of the application was successful you will be redirected to a page like the one shown in the following image.
Now click on “Settings” (that you find in the side menu of the page) and fill in the “Namespace” field with a name to identify the application.
Then click on “Add Platform”, select “Website” and insert your site URL.
Go to the “App Review” section and ensure the application is public.
The last step is to copy the APP ID and paste it within the plugin settings dashboard.