Plate Frame Heat Exchanger Clarifications Required

[Iomcube]

I have gone through a Plate&Frame heat exchanger [PHE] manual by Chinese vendor & I want to share some extracts from it.
The coloured lines I couldn't understand & ask people here to elaborate on these

Following are extracts:

 Typical working pressure 10bar
 Typical temperature ranges 150C
 PHE providing condensation duties are used in tandem with temperature decreasing small capacity tubular exchanger which increases capacity for vapour treatment
 PHE combines two types of corrugated plates such that cross-section area ratio of channel is 2:1

 This is important for almost equal heat transfer duties for two fluids at different flowrates​

 In case flowrate ratio is 1.8 - 2.5 nozzles on PHE are unequal sized. Smaller nozzle with narrow flow channel for smaller flowrate media & vice versa​

 PHE structure of opposite angle flow reduces flow dead area of fluid as a result heat exchange effect increases
 In the central heating arrangement the flow rate of primary heat medium is usually one half of flowrate of quadric heat medium so that our PHE is more suitable for central heating arrangement
 According to flowrate b/w plates temperature difference & technology conditions the PHE can be divided into single flow path & multiplex flow paths. Usually mediums with temperature difference larger than 1.8 times LMTD should use multiplex flow paths. Appropriate flowrate b/w plates is 0.3 - 0.5 m/s. If the flowrates is too low two flow paths or multiplex flow paths should be used
 Doniel Bernoulli & Euler criteria equation of all kinds of PHE, average equivalent diameter & average cross-sectional area of low channel are shown below:
I cannot understand how to use this table & how it can help me in future PHE selection