AThis is the end of a bullish climax (to the left of where this chart begins). It is punctuated by very high volume. Draw a horizontal line on top of the highest point. This is the supply line where selling occurs to push the price back down until the stock of future escapes the trading range.
BDraw another horizontal line at the lowest point where the prices have gone almost straight down. This is the demand line where buying occurs to stop prices from moving below the trading range.
CThis is a "spring". Price punctured the demand line but recovered later in the day to move back into the trading range. This is very bullish because it shows that demand overcame supply to prevent more loss.
DThis drop towards the demand shows a successful test of the "spring" at point 'C'. It is a good test because the bottom was above the demand line and the volume was a little lower. This is the first buying point in this trading range.