Hi Dave,

Don't worry, it's actually quite easy to change the column headings from numbers to letters in Excel. Here's how you can do it:

1. Click on the "File" tab in the top left corner of the Excel window.
2. Click on "Options" at the bottom of the left-hand menu.
3. In the "Excel Options" window, click on "Advanced" in the left-hand menu.
4. Scroll down to the "Display options for this workbook" section.
5. In the "Show this number of Recent Documents" field, change the number to "0".
6. In the "When calculating this workbook" section, uncheck the "Use 1904 date system" box.
7. In the "Editing options" section, check the "Extend data range formats and formulas" box.
8. Click on the "OK" button to save your changes.

Once you've done this, your column headings should change from numbers to letters. If you have any trouble with these steps, feel free to ask for further clarification.