To enable Facebook Login you just need Facebook App ID and App Secret.
how to getting Facebook App ID and App Secret.
Check this link. How to Create Facebook App, App ID, and App Secret
Note : copy redirect url from Your admin > Setting > Social login setting
After getting App Id and App Secret, you have to setup your admin panel:
- Go to your Admin panel -> Setting -> Site Setting -> Social Login Setting
- For Facebook: set 'Facebook App ID' and 'Facebook App Secret'
- For Google: set 'Google app ID' and 'Google app Secret'
- And save your changes.