The rule is simple.
When MACD crosses up, it is supposed to give a buy signal. However, before entering into a Long position, there is a need for a confirmation. This confirmation can be from a down trendline breakout or from another indicator.
In this case, I've chosen the Exponential Moving Average Cross to be as the confirmation.
The Buy Signal will appear when there it fulfills the following conditions:-
i. The MACD line is above the Signal Line
ii. The fast EMA crosses the Slow EMA
The Sell signal will appears when the opposite of the above condition is met.
This indicator is meant for the Swing Trader whom would like to hold a position for a long time.