This documentation is not using the current rendering mechanism and is probably outdated.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.

Defining the default language

You should define which language is your default language, i.e. the ISO code of the language which will be shown with the parameter L set to zero. See the TypoScript Reference for the property defaultLang below to see how how to set the default language.