Use the templates as an honest starting point
A spreadsheet can be the right answer for a small volume controlled by one buyer. The downloads expose the fields needed for purchase order import, open-order reporting, and promised-date follow-up without requiring registration. They are designed to help a team establish clean source data before buying software, not to manufacture a false product dependency.
Preserve ordered and committed values separately
Do not overwrite the requested date or quantity when a supplier proposes a change. Keep source values, supplier proposals, buyer decisions, current commitments, owners, and timestamps in separate columns. That structure makes a later migration safer and prevents the most recent spreadsheet edit from erasing the commercial history.
Know when a file has reached its limit
Move beyond a spreadsheet when multiple buyers edit the same status, replies are copied from email, reminders depend on memory, suppliers propose several line differences, access cannot be scoped, or management needs an attributable event history. At that point, test software with current open orders and keep the export as a reconciliation path until the team trusts the new workflow.