Don't worry about the questions, that's what we all live for in here LOL. And I like trying to answer, now that I (think) know some of the answers
If it's 3 piece, then it would have a battery, screwed to that would be the atomizer, and then pushed into that is the cartridge, which holds the juice. If it's 2 piece, the battery, then screwed into that is a longer piece which holds the juice and atomizer in one, that's the cartomizer.
If you have the 3 piece, then the atty is what you would put the drip tip on in place of the cartridge. This is where you would put a drop or two for tasting, right down the drip tip onto the atty. Does this help at all?
You can also google e-cig difference between 2 piece and 3 piece, or atomizer vs cartomizer, and get a better picture.
And the cartos, or cartomizers, I just top off before they get too low, and when they start to have less vapor or flavor or TH, then you can clean them, or at around $2 a piece, you can toss and start with a new one. I have been getting 1 to 2 weeks out of my dual coil cartos, so I think I got my $2 worth. Any more questions don't hesitate.
Balth