As described in the guide, aircraft need to be configured for each route based on demand in order to minimise empty seats and lost revenue. One could adjust the seat numbers manually but multiple calculations would have to be made to ensure that the config matched the demand. An easier way to do this would be to use this calculator, note that a first class seat requires 4 economy seats spaces and a business class seat requires 2 economy seat spaces.
To use the calculator below just enter the route demand for each class of passenger and the maximum economy seat configuration possible, i.e. the number of economy seats if all seats were economy. Then hit calculate. The results are the number of seats for each class that you need to configure.
Example: A Dassault Mercure can be configured to have a maximum of 150 seats (all in the economy class). Your intention is to fly this
A/C to a destination with 98% Overall Demand, 15% Economy Demand, 25% Business Demand and 60% First Demand. Within the calculator below
enter 15, 25, 60 and 150. The result will be the ideal configuration of the A/C seats - 7 Economy, 12 Business and 30 First.