Here some of the underlying conventions are explained in more detail for the user who wants to write his own modules; but the section is also useful for the normal user to understand how PaPCo does things.
No great detail of how to write your own add-in module is given here, this is covered in the section 6. Instead, we present here the general rationale that all the current modules of PaPCo adhere to, to give the user an idea of what he is letting himself in for when he attempts to add his own module.
Remember that PaPCo prescribes very little. However, if you want to produce nice output that works well in concert with other modules, then it makes some sense to adhere to some common philosophy.
If reading this section discourages you: don't be. The actual amount of work to add a new model is quite small - doing it the first time will probably take you a day. Eventually new modules can be added within an hour - although it might take longer if you want to make use of all the functionality of PaPCo.