You have the option to add your own product, not from a specific website.
Go to the dashboard, then select "Bulk List," and click on "New Item."
![](images/Import_your_own_products1.png)
Next, insert images from your PC, add a title, description, and price for the product. Then, click "Save the Product.
![](images/Import_your_own_products2.png)
After saving the product, you can run bulk listings to any marketplace. Here is a guide for bulk listing.