Customizing means editing rows and columns; you can add or remove rows and columns as you deem fit. A blank spreadsheet has hundreds of uses. If you cannot figure out how to use the template, try to do more research on 50 ways to use Sample Spreadsheet Templates.
A budget spreadsheet template can help you make your budget plan painless. Instead of creating a budget of the top of your head, download this template and enter relevant data on the fly. The most important info that goes into the template are items to purchase, cost per item, and the total costs of all items.