Write an article based on this "Open Numbers. Create a blank spreadsheet if you like. Browse the available template categories. Select a specific template to use. Click Choose. Fill out the template if necessary. Know where to place your data headers. Select a cell. Enter your data. Save the data. Enter any other necessary data. Add cells together. Save your spreadsheet."

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Click or double-click the Numbers app icon, which resembles a series of white, horizontal bars on a light-green background. If you want to create a blank spreadsheet, do the following and then skip ahead to the "Know where to place your data headers" step: Click the All tab in the upper-left side of the Numbers window. Click the Blank template in the upper-left corner of the page. Click Choose in the lower-right side of the window. On the left side of the window, you'll see several tabs (e.g., All, Basic, etc.). Clicking a tab will display a list of templates in that category. You can also just scroll down through the list of templates in the middle of the page. Click once the template you want to use to select it. It's in the lower-right corner of the window. Your template will open in Numbers. If you're using a pre-formatted template, fill out the necessary cells to complete the template, then skip ahead to the "Save your spreadsheet" step. Skip this step if you aren't using a template. Some templates use multiple spreadsheets which you can switch between by using the tabs in the lower-left side of the Numbers window. You'll usually place headers in the 1 row at the top of the sheet. For example, if you're creating a list of employee names organized by department, you might place one department title in cell A1 and another in cell B1, etc. Click once the cell in which you want to insert data. For example, if you want to type the word "Date" into the cell A1, you would click cell A1. Type in the word, phrase, or figure that you want to enter into the cell. Press Return to do so. Your cell's data will be formatted and saved. You can fill out the rest of your spreadsheet as you please. If you want to use a cell to combine the results for a list of cells into one sum, you can do the following: Select an empty cell. Type in =SUM( followed by the cells you want to add in "A1,B1,C1" format and a closing parenthesis (e.g., =SUM(A1,B1)). Press Return. Review the sum. Once you've finished creating the spreadsheet, you can save it as a file on your computer by doing the following: Click File in the upper-left corner of the screen. Click Save As... in the drop-down menu. Enter a file name. Select a save location (you may first have to click the "Where" drop-down box to see a list of locations). Click Save.