I guess there is (yet) no official English translation for
https://www.ilias.de/docu/goto_docu_cat_3663.html
in the category itself.
The buttons on the right lead to PDFs to apply. These you'll find in the following category:
https://www.ilias.de/docu/goto_docu_cat_1726.html
"About ILIAS society" (PDF) will be more or less the translation of the mentioned text above.