Buy and Sale signal

i m using AB. I want to know when it gives buy and sale signal by the crossing over by various moving averages like EMA, SMA and WMA. Pl upload a chat for better understanding.
thanks in advance.

Example:

Buy = Cross( MA( C, 13 ), MA( C, 55 );
Sell = Cross( MA( C, 55 ), MA( C, 13 );