How to add standard deviation of profit and losses as a custom backtest metric

Would someone be kind enough to provide a detailed explanation as to how in the world I may add the standard deviation of profit and losses of a system as a custom backtest metric?

I have spent days (maybe weeks) reviewing pages on this forum including:

and no luck.

Please help.

Are you able to create a high-level CBT and output ANY custom metrics? It would be helpful if you posted your best attempt at coding this yourself so that others can correct your mistakes.

How about using forum search?


Words can not express how I feel right now.

Thank you very much kind Sir!