Migration guide
A good import saves days. A messy import creates duplicate items, wrong tax, bad barcodes and stock confusion.
The product list starts clean, so billing, inventory, purchases and reports are easier from day one.
Run a test day, print receipts, close cash and verify reports before making Posnic the live counter.
Keep a backup/export from the old method so old invoices and balances can be checked later.
Billing habits change only when staff know sale, return, correction, payment and day-close rules.