Start with the evidence
Read the source headings and inspect a known transaction before transforming the data. Preserve the original export so a conversion can be checked independently.
Work through the example
One file shows a USD50 purchase as −50; another uses 50 in an outflow column. Adding both as positive inflows would reverse the meaning even though the digits were copied correctly.
Make the next step clear
Document the convention used in any working sheet and test it with a small example. Resolve ambiguous fields before using the transformed totals in a review.
Keep the source context
These guides describe how to organize a statement review. They do not request bank credentials or imply that a bank connection can initiate transfers. Keep original descriptions and account references appropriately protected while preserving enough context for authorized review.