Export the Product Inventories / Similar Products file:
If you haven't added any Similar Product items yet the file will just have headers in Row 1.
There are 2 fields as shown below. Both need special attention as they link to other sections. If a product is associated with 2 other products you'll need to add two line items:
Seller Product ID (Required)
User defined product identifier for the Product. This field needs to be the same as the seller product identifier defined in the Product Inventories General Data sheet.
Related seller product ID (Required)
User defined product identifier for the Product. This field needs to be the same as the seller product identifier defined in the Product Inventories General Data sheet.
Once you've added all your details, save as a CSV and import the file by going to import:
Clicking on Product Inventories opens up a side panel. Select Similar Products from the Select data dropdown list, select the CSV file to be imported then press the blue import button.
The import process will only complete if the file has no errors. If the file has errors an error log (in CSV format) will download to your download folder. Open this to see any errors flagged with a description of the error. Fix the errors and re-import.