With how CPP is structured we always recommend following this guide to ensure you have a record of all of the products you have in CPP. This allows you easily download all of your products in one file for you to manage.
For my example, I will use how we show our Licenced Content in our database works. You will see below we have the main category (Star Wars) and all of the subcategories are shown underneath them.
We regularly download all of the subcategories and place them into the top tier. This allows us to export an entire range of products at once.
The first thing you need to do is to go into anywhere where you have products and particular categories. From here you need to use the retailer product feed to export the products from CPP.
Once this has been completed you will need to keep just the product ID column. You will need to add a new column with the header set as "categories" which you will then add the top tier category ID onto each product.
Once this is done you will need to finally save the file as a CSV (UTF 8 and quote all text cells) and import the file into e-commerce import.
Now when you load the top tier you will see all of the products which you wanted. You can now do an export to have a catalogue of products from CPP.
Please be aware this should be updated on a regular basis once new products have been added.