For Facebook Auto Post, you will need to get Facebook Application ID,Facebook Application Secret and Facebook User ID.
To get all the required details you will need to create a Facebook APP here.
Also please make sure you follow below steps after creating app.
Navigate to Apps > Settings > Edit settings > Website > Site URL.
Set the site url as :
Once you add the account, then you will need to authorize the account.You can authorize the account by clicking "Authorize" button at top left of the account settings section.Once you click on Authorize button you will be redirected to the facebook which will show a dailog box asking the permission to post on your wall and get all the details regarding your facebook pages related with that account.You will need to allow all the permission to enable the auto post to your profile and fan pages.
Please check our below video for proper setup of the plugin.