Step 1:

Select the app Accessorize from Apps section.

Step 2:

You can download a sample from the link, to see how is the structure the csv file to fill the information

Step 3:

The first column is the main product. You can put any SKU from any enable/active product. The second column is the SKU product that will be the accessory from the main product. If you need to put more accessories to main product you can repeat the SKU from the main product column.

Step 4:

Upload the file to begin uploading the information.

Step 5:

You will see the content details about the products and accessories.

Step 6:

If you check the product page of your product, you notice that will appear extra content before add to cart button, displaying products as accessories.

If need to make changes, just re-upload the csv file and it will be updated.