MACD Means Moving Average Convergence Divergence. It consists of histogram, signal line and base line.
Whenever the signal line goes above base line its a buy signal and whenever it goes below base line its a sell signal.
Histogram also plays a very important role. When the base line and signal line are below Histogram it is considered as bearish and whenever above histogram it is considered as bullish.
Trading using MACD seems easy but still it needs a good knowledge and understanding as sometimes there may be a wrong signal as well.