A warehouse is a pool of stock. Channel locations map to warehouses. Every connection has three switches per warehouse: - Sales – its orders count as demand. - Stock – its stock levels are the truth for that warehouse. - Purchase orders – POs can be raised/received against it. Rules: one Stock source per warehouse; one Sales source per channel; duplicate orders removed. Example: Shopify + eBay ship from your unit, Mintsoft runs it → warehouse ‘Main’: Shopify Sales on, eBay Sales on, Mintsoft Stock on and PO on.