Prepare the spreadsheet. Note that the base variant(s) must exist before importing. Provide the item code and the item description:
Add the name of each option and the value of that option for the specific item.
Click on the Cog -> Import Center -> Variants -> Variant & Items:
4. Select the file and click on 'Upload'
5. Check the success message for the number imported, and if the import has worked, the variants are ready to use.
6. The example import gives this: