If you look carefully at the chart, it is easy to note a common situation: the price of the asset is rising, it reaches a certain level, and then reverses downward. Below, it also seems to rebound off an invisible obstacle and again moves upward.
The obstacles below and above are called levels of support and resistance. Upon reaching them, the chart is likely to reverse in the opposite direction. This is the reversal moment you need to notice in order to make a profit.