This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
The extension should be installed as usual using TYPO3 Extension Manager. Notice that this extension can work only as a system extension. It requires at least TYPO3 6.2 and PHP 5.3.7.
After installation OpenID identifiers should be added to the Frontend and Backend user records who need to authenticate themselves using OpenID. See the "Configuration" section later in this manual for more information.