Set Auto publish on editing posts/pages/custom post types as Enabled.
On bulk/quick edit or normal post editing the posts will be auto posted to Facebook.
You can also set the auto publishing to Yes from the metabox on post edit page(https://ps.w.org/facebook-auto-publish/assets/screenshot-3.png?rev=2124301) of the specific old posts which you want to auto publish to social media(without changing the settings).
Bulk publishing without editing each posts is a premium feature.
Hope this helps.
Thank you.
