Trace every instalment: the sale agreement and valuation, each payment and the account it landed in, any holding company that received or distributed it, the tax returns reporting it and the transfers moving it toward the investment. Gaps are explained with records, not statements.
How to sequence the file
Build the file in the order the money moved. Hypothetical example: a Lévis couple sold a manufacturing supply business to an employee group and were paid over four years, partly by vendor take-back loan repayments into a holding company, which then paid them dividends. Start with the original acquisition of the business, since the officer will ask how they came to own what they sold.
Then the sale agreement, the valuation, the loan repayment schedule, the holding company's statements for each year, the dividend resolutions, the personal tax returns showing the income, and the bank statements for each transfer. Finally the conversion to U.S. dollars and the wire to the enterprise.
Have an accountant prepare a one-page flow chart keyed to the exhibits. Where a record is genuinely unavailable, obtain a replacement from the bank or the notary rather than writing an affidavit first; affidavits are a last resort.