1st chart (Call + Put volume)
Shows you the volume of contracts traded on the current day. However, it could be misleading. If a put is STO it will show a volume spike on the put side and could be misinterpreted as bearish. Remember STO puts benefit from the upside
2nd chart (bull/bear volume)
Better to understand the sentiment on the trades as it will show you if the positions are bullish or bearish regardless of being a call/put. For example, if calls are being traded at the Bid it could be assumed as STO (bearish) rather than showing a green bar like the volume chart, it will show a red bar indicating that although the spike was on calls the positioning is bearish
3rd chart (Call/Put net premium)
Subtracts the bid from the ask on calls and puts in order to get what is known as the Net Premium. If more calls are being traded at the ask than at the bid the net premium will spike to the upside. When the net premium is above 0 (positive) it means that more calls/puts are being traded at the ask and when the net premium is under 0 (negative) it means that more calls/puts are traded at the bid. This chart shows you both separately so you will find times when both calls and puts net premium are positive/negative simultaneously
