As you may or may not know, there is a built in user guide within your SD software. It can be accessed by going to help>>Softdent help. From there you can search for various topics.
However, did you know that you can also access the user guide based on the open screen that you have by selecting F1 on that screen, including report setup screens?
For example, if you are looking to see how an account aging report pulls its data, you would go to reports>>accounting>>account aging. You would select your output option then you will be at the report setup screen. By selecting F1 on your keyboard, this will open your SD user guide already on the topic of running the account aging report.
For this report in particular, you will see below step 7, a link for an explanation of the report fields (see below screenshot). This will display, in bullet point form everything that is on the report, including what codes SD is generating this data from.
Different reports will have different number of steps, but most will have an explanation of the report fields. This is a great way to better understand and breakdown the information with your SD reports.