1. Open the spreadsheet in the 'Numbers' app.
2. Select 'File' in the upper left-hand banner.
3. Hover over 'Export To' in the drop-down menu.
4. Select 'CSV.'
5. A pop-up window will appear, select 'Next.'
6. Enter a file name, and select a location to save the file to.
7. In the 'Advanced Options' section, select 'UTF-8' for text encoding.
8. Select 'Export.'