The main way to use this is that you set a threshold and a visual is given when the difference between the high and low is less than the threshold. This should be an indication that the market is ranging.
There is also an option to show the opposite (when the difference is greater than the threshold) which has no purpose other than to show the opposite state if you want to see it.
It is designed to be used both on and off the main chart - just put it where you want it and choose the appropriate "show" options.
People also use the Aroon to show ranging when both the high and low are going in the same direction. There is an option for this however keep in mind that it misses the first bar of that happening. This can't be gotten around without going to lower time frames which can't be (at the moment in TradingView) dynamically selected automatically, the lower time frame has to be set by the user so for now it's better to just fill the first bar the two are going in the same direction mentally when you see it.
Additionally it defaults to the normal colors we are familiar with for up and down (long/short) but you can choose Aroon colors if you wish with just a checkbox.
Finally, if you find value please do make a comment, give a thumbs up etc.