Here are the basic rules to read better volume indicator:

Red bar - wide range, high volume (climax bar). Can be seen at beginning of uptrend, end of uptrend., and in continuation of downtrends.

Green bar - low range, high volume (high churn bar). Can be seen at beginning of uptrend, end of uptrend, and continuation of downtrend.

White bar - low volume, high range (low churn bar). Can be seen at bottoms, tops, and continuation of uptrend.

Yellow bar - low volume, low range. Seen at similar places to the low churn bar(white bars).

Magenta bar - Climax volume plus High volume churn - both the conditions are rare.