Once you have a journal file representing a recent history of your
finances, the next step is to generate reports in order to give richer
meaning to this data.  For example: Where do you spend your money?  Do
you have enough to cover upcoming expenses?  Are you creating or losing
net worth?  Are your investment performing well?  All of these questions
can be answered easily with Ledger---if you know how to ask them.

Preparing complex reports is not a simple task, but neither is it a
difficult one.  All that's required is a proper understanding of how
Ledger views your data, and how it prepares it for reporting.

After Ledger reads a journal file, it creates an in-memory
representation reflecting the order and composition of those transactions.