Just install the extension and choose the preferred skin and language. The preferred language can be set only in the user/group typoscript configuration field. The option is called: “tx_date2cal.prefLang”. You can use language codes from TYPO3 (TDL), because “date2cal” converts them always automatically to ISO 639.

In version 3.1.0 a new option was introduced: “tx_date2cal.secOptionsAlwaysOn”. Set this option to “1” if you want to activate the “show secondary options (palette)” always as default for the user/group. The user can deactivate the option temporarily for a page. Please note that the settings is only restored if the form contains a date or datetime field.

Furthermore all global options can be overridden by the user or group typoscript configuration. You can find all possible configuration variables in the global settings dialogue of "date2cal" via the extension manager.