I would recommend getting comfortable with some basic double-entry accounting software like GNUcash [1]. I found that extremely helpful in learning how to reason about these things, as well as grasp the purpose of different types of accounts (asset vs A/R vs income etc). They also have pretty good docs and tutorials as I recall.
Also then it'll quickly show you where the existing software falls flat (and it does) in terms of scriptability, scaling, etc.