Build a model
In building a model, you must first understand what you are trying to model and what restrictions apply.
The restrictions lead to a series of equations that must be discarded because they are not applicable within the context of the model.
Once the equations are clear, we proceed to list the associated variables and evaluate to what extent there is a need for multiple copies of the same variable and with it associated equations.
Finally, the network is assembled, which leads to the detection of possible missing relationships or variables that have not been considered. Once these deficiencies have been supplied, we end up with a totally interconnected network, with equations and multiple versions of these and lists of variables, their meanings in the context of the model and their association with the variables of the equations.