Hello Robert,
You can find an example in our knowledge base. It is an older article, but the idea and code is still the same. It shows how to import products from external source (this depends on your choice) and the API you will use to import the products. In the example is used Excel sheet as a source. The article can be found here -
Products import from external source.
Although it does not contain package for version 7, I can send you an updated package if you write us an e-mail to support@kentico.com.
Best regards,
Filip Ligac