To set up the 'Attachments' add-on:
  1. In the administration panel, go to Add-ons > Manage add-ons.
  2. Enable the Attachments add-on (change its status to Active on the right).

To attach a file to a product:
  1. In the administration panel, go to Products > Products.
  2. Open the details page of the desired product.
  3. Open the Attachments tab and click the Add attachment button.
  4. Enter a name into the Name input field and upload a file in the File option in the opened form.
  5. Click the Create button.
    NOTE: A customer will be able to download this file in the Attachments tab on the product details page in the storefront.