Trend(OBV) uses True Strength Index to analyze "On-Balance-Volume", which measures buying and selling pressure as a cumulative indicator.
Horizontal lines and zones are supports (entry for bulls and exit for bears) and resistances (exits for bulls and entries for bears). Diagonal lines from Fib channel/fan are for trend-determination and additional levels for active trading. The market is actively moving so the entries and exits constantly change. Trade small if you want to practice!