You create a Sale using the Sale window. Access the Sale window by clicking the Cashier menu at the top menu bar then select Sale.

Customer Selector Customer for this Sale, for Walk In customers select (Walk In)
New Button Creates a new Customer and assign the new Customer to the current Sale
Status Button Shows the Terminal Status window, this is used together for Cash Float feature (See Cash Float article)
Terminal Selector The terminal in which this Sale is being made
Branch Selector The branch in which this Sale is being made
Collected Button Toggle the selected sale item between Collected and Not Collected state. This is used for Partial Sale. (See Partial Sale article)
Quick Keys The right section is used for Quick Keys allowing you to select items quickly, especially on touch screens. (See the Quick Keys article)
Completion Date If this is not a Partial Sale, this must be set to the Sale date. Otherwise, select a future date when the Partial Sale will be completed.
Shipping Shipping fees for this sale, typically used for online store purchases. If no shipping fee is incurred, set this to zero
Payment Completes this Sale by entering the payment details in the Payment window

When you click the Payment button, the Payment window will be shown. Enter all the payment details in this window and click Save. If no payment is being made, simply click the Save button. For more details on the Payment window, see article Sale Payment, Completion Payment.