Here is a good source to understand about MACD:
https://www.investopedia.com/terms/m/macd.asp
And how to use MACD Divergence to find a possible reversal.
https://www.investopedia.com/articles/forex/05/macddiverge.asp
And some other ways on how to use MACD
https://www.investopedia.com/articles/technical/082701.asp
You Will notice that none of them mention oversold/overbought
I was more like interested in MACD as a tool for oversold/overbought conditions. There are more articles about it, but this one looks quite explanatory.