Struggling

What and how much what?

Your food log should include everything calorific that goes in your mouth. To do this most accurately, you would have a food scale to weigh solids, and some measuring cups/spoons for liquids.

I prefer to pre-log, then prepare food using the amounts I've logged.

Yes. You log what you consumed. If you made a batch for your family or to eat leftovers later, you can put it all in the recipe builder.

Edited to add this excellent read: http://community.myfitnesspal.com/en/discussion/1296011/calorie-counting-101

Ideally you should weigh the foods before you cook them and then log how much of that you ate. Say you used 16 oz of ground beef for meat balls and you ate 1/3 of the finished amount you would log 5.3 oz of ground beef (16 divided by 3).