1. Look for the open, high, low, close on the chart that the price levels on the tool have to MATCH. You can also use magnet mode (it locks over the bar you want).
Swing the arms from either end once the center is over the bar and at proper level, then take the end that is not the center and place it precisely in the same way on the other point (looking again for the bar to match). I only use the the high or the low, depending on whether it's a top or a bottom.
You may be pleasantly surprised at how well this works. Try it out.