This document provides instructions for using a cash register application on a mobile phone. It outlines 4 main steps: 1) Manage Item to input inventory items, 2) Buying to record purchases and restock inventory, 3) Selling to process sales transactions, and 4) Report to view sales reports. It describes how to add new inventory items, make purchases to restock, scan barcodes during sales, change item prices if needed, and view sample sales reports in a CSV file format. Donations can also be made within the app to remove limitations on daily transactions and remove advertisements.