Where you see the blue arrow on the chart represents the orders that were not filled hence the reason why you see price rise with a strong upsurge (the semi lengthy green bar shown by the blue arrow). When price returns to "buying area" known as supply, more of those orders that were not filled initially will be filled. If all of the orders are filled you will see price fall through the buying area and continue downward. This too will present a buying opportunity. If not all of the orders are filled, then you have an opportunity to go long from the "buying area-supply" zone. Watch for either scenario to play out and execute a position accordingly.