This package installs an checkbox attribute for pages that lets you mark a page type. Now whenever a page of this type is published, this will trigger the submission of this page to Twitter via the Twitter API. This way, any publishing of a blog post, an event or anything else you associate the attribute with will automatically be tweeted from your account.
To make use of the Twitter API, you need an developer account at Twitter, from there you can obtain the necessary Keys that are needed for authentication. Request your developer account at apps.twitter.com. Keep in mind that the account you connect your developer account to will be the publishing account for those tweets. In your dev console, you can add an App from where you get your credentials.