Understand the Register Layout

Customer area: Search, select, or keep the Walk-In Customer.
Sale/Refund switch: Determines whether newly added lines are sales or returns.
Product entry: Search by name or scan an IMEI, serial number, UPC/barcode, or SKU.
Cart: Review item name, quantity, price, discount, and tax.
Notes: Add receipt notes, customer notes, or a reference number.
Totals: Review subtotal, discount, tax, surcharge when applicable, and amount due.
Actions: Hold the cart, cancel it, or continue to checkout.