If you are not a developer, you need to register as a developer.
Click on the “Register as a Developer” link (highlighted above).
In the first step “Accept the terms” and click continue.
In the second step “Tell us about you”, select the appropriate section and click continue.
Now you are a Facebook Developer. Click “Done” and you can now create the application.
Click on the “Create New App/ Add a New App” link.
If you have a developer account in facebook, click on the ‘Apps’ link in the header and you can create a new app.
Select the platform “Website”.
Now enter the app name and click on the “Create New Facebook App ID” or click on the “Skip and Create App ID” button.
In this page enter your App Display name, Contact Email, select the category and click “Create App ID”. It will show a captcha to select some pictures.
Enter the security check and click “Submit”.
The App ID and App Secret are now ready. Click the “Show”button to see the App Secret. (The app secret is in alphanumeric and DON’T use ******* as App Secret.)
Now go to the ‘Settings > Basic’ page of the app.
In this page click on the ‘+ Add Platform’ link. It will display some platforms for the app.
Here select the platform ‘Website’ and display the section to enter the website details.
In the “Site URL” section, enter the url of your site and click “Save Changes”. (Note: You can see your site URL in the top of the plugin facebook settings. See the below image)
Here the app is in development mode. Only the developer can view the posts now.
To make the app ‘Live/Public’, please go to the ‘App Review‘ page.
In this page please select the ‘Live/Public’ mode by selecting the ‘YES’ button. (Sometime it will ask for the contact email address to make the app live. In such a case, please go to the settings page and do as given below. After completing the 2nd step please return to this section and make the app live.)
Now a ‘green indicator’ will display next to the app name as in the above image.
You can now use the facebook app keys in the plugin. There is no need of submitting the app for approval.
Now enter these keys in the plugin settings in your site.
After entering the keys in the facebook settings page, you need to “Authorize” the account. (The authorization section is present in the wordpress plugin section).
You can see the FB pages in the settings page only after authorizing FB account.
When you click on the “Authorize” button, it will redirect to a facebook popup dialog box.
There is some warnings and you can ignore the warning and click the “OK” button.
Select the “Public” option and click OK.
In the step 3 click OK and the authorization is complete.
Now you can see all your fb pages and you can select the fb page to auto publish.