How to create a Facebook App:
Please go at this url https://developers.facebook.com/apps and click on 'Create New App'.
Note: If you can't click on 'Create New App', you need first to 'Register as a Developer'.
Then the creation of new app will be available.
Please note that only real personal facebook accounts have permissions to create an App. Business accounts can't manage facebook Apps.
Fill in your 'App name' and click continue.
Enter the required captcha challenge.
Once on the basic settings of your new app:
For the field 'App Domains' enter your blog domain name (example: mydomain.com)
Sandbox mode should be disabled.
In the field 'Website with facebook login' enter your blog url. (example: http://mydomain.com)
Copy your 'App ID' and 'App Secret' and configure your facebook account in MicroblogPoster's social accounts section.
Once you've added your facebook account, MicroblogPoster will provide you a link to follow in order to authorize (i.e. link) the account with your App. Follow that link and authorize your App posting on your behalf.