Adds it to the catalogue and, where you type a price, to that price list. Kit contents are added afterwards from the detail panel.
Leave a sheet blank to keep the product off it. Spiff columns appear only on sheets that carry them — everywhere else an incentive is set per account, on the account's own Pricing tab.
A sheet products are priced on — one per commercial arrangement, the way the master workbook has one tab each for CO, AZ and the CBA variants.
An account is pointed at a list by name on its own settings, and the card importer matches sheet names to these. Two lists whose names differ only by spacing are the trap worth avoiding.