How Wirecard committed fraud?” What was the fraud, what did they do, how did $2billion goes missing

Wirecard AG – A former analyst favorite in Germany, Wirecard, AG recently revealed a potential $2.2 billion fraud.
Please explain the specific accounting behind the fraud.
Example – What and how did Wirecard do to commit fraud, etc.. Please also address the role of the auditor in this situation.
You also can use bullets points, summaries and exhibits to help organize your thoughts and convey information in an effective and concise way.

The specific instructions is to state “How Wirecard committed fraud?” What was the fraud, what did they do, how did $2billion goes missing, etc. And the other was to state what role of the auditor in this case was?