Adding a calendar to the appendix

I am writing a report in Latex and would like to append a calendar in the appendix. I found this calendar and it looks really nice, but I have no clue how I could append it to an existing Latex document in the appendix, since the examples for this calendar make use of an own document class. In the best case, it should be possible to reference the calendar in the other parts of the document. Is there an easy possibility to achieve this?

Thanks in advance!