To Import Item Options go to Back Office, login your account and select Items under Listings.
Click on the more options.
Select Import Item Options.
Click on Download Template. An excel file with the template will then be downloaded.
This is what's inside your template.
Remove rows of the items that doesn't need an item options, then encode your Item Options like the sample below.
||| Note: Don't change all under Row 1 and all under column Id and Item Name
When your are done adding Item Options save the file then go back to Backoffice where you import the template, then click Browse to upload the file and click OK.