No question is stoopid.
The concept of a fATPL was dreamed up by HR to save on tiresome keyboard typing as to what qualifications they want from any pilot wannabe applicants.
Let me try and explain. First you will need to have a PPL. I see you have this so jolly good. Second you will need to enrol on a course to teach you the ATPL groundschool. There are many schools that do this either by distance learning or by residential. For more info use the search function else you will encounter the wrath of young scroggsy the moderator.
After you have theory under you belt and the required hours, you will need to sit the practical side on training, namely the CPL, Multi Engine and the Instrument Rating. Once successfully passed you will be the proud owner of one fATPL. Please note, that this is not an actual licence it is only a term to mean you have a CPL and an IR.
You must have completed the training for the night qualification prior to CPL issue and hence is a requirement for a fATPL.