How it's different: It comes with support and resistance levels and is colored based on the trend it's in.
How to use it: There are various ways to use it. I believe the most common way is to buy once the ROC crosses over the 0 line, and sell once ROC crosses under the zero line. My suggestion to use it with Heiken Ashi candles. Assuming you're looking to take a long position on a stock: Be patient, wait until the ROC line start making new lows (this will be apparent because you will be able to see the support level dropping. Then for ROC to stop making new lows and start showing a positive or upwards slope. If the slope is positive and the Heiken ashi candles are also bullish (i.e. turquoise colored and rising), then enter the trade, and you can either: (1) wait until Heiken ashi candles become bearish (i.e. red color and falling). or (2) if the ROC above zero, you can be somewhat lazy and hold even while it's falling as long as ROC remains above zero. Then you would sell when Heiken ashi candles become bearish. (so the 2nd option is just deferring the sell).