This indicator is clearly helps you to find overbought or oversold points with alerts. You can use it for buying when it shows up or selling when it shows down. Also it is useful for supporting other strategies like trend bands. When in an uptrend you can buy with the up arrow or in a downtrend you can sell with a down arrow.
You can use it on every currencies but it is more efficient on major currencies. It works on every timeframes but you can find the best one for you.