Simple for modular:
You do all the 7 exams required to get a PPL (assuming JAR here).
Then, you do all 14 for the ATPL. Even though some of the modules at ATPL level may have the same names as ones you already passed for your PPL, they have very very different contents!
If you only want a CPL (not ATPL) then you only have 9 of the 14 ATPL examinations to pass.
JAR requires that you do 10% of the course time with an apporved training organisation in a classroom environment-so you can't simply book yourself in.
There are also only 4 centres where you can take the ATPL exams.
Hope this is useful
B