The more points connected, the stronger the trend, and the more significant an eventual breakout. Trendlines usually show levels of Support and Resistance. Looking at the slope of the trendline, a succession of lower price valleys is a bearish. Used in constructing Keltner Bands. Volume is the number of shares or contracts traded during a given time frame - often one day.
Volume confirms the price trend when it increases with an uptrend and decreases with a downtrend.
Volume changes often precede price changes. As volume increases, prices usually also increase.