Quick tutorial on Bookmap and it's use for order flow. 

Volume dots represent the traded volume per time at a specific price. The bigger the dot, the larger the volume is.
Volume bars represent the volume traded in a given timeframe.
Best bid and offer lines represent price for the highest buyers and the lowest sellers.
The point of control (POC) is the price level that had the largest size of a measured activity during the sampled period.
For example, if the measured activity is traded volume, POC will be the price level at which the largest aggregate volume size was traded during the sampled period.
Bookmap displays configurable columns to the right of the chart and enables the user to analyze the order book behaviour per price.
Each column can be configured to display the following types: Current Order Book, Volume, Trades Counter, Quotes Counter, Quotes Delta, and Custom Notes.