How do I edit my collection after upload?

You can make changes to your master spreadsheet and then re-import the file into Ribbon; it will update existing SKUs. You can also manually add a new item, or edit individual items. 

Any changes to your master product file and to your assortment will also need to be made visible to your agency. It is advisable that you make updates by reimporting a product CSV file. 

Uploading a new product file will not automatically delete a product. This is a safety measure. The only way to delete a product is to click on that product, click on Edit, and then on Delete. If you want to remove a product that has sold, it is best to not delete it but to "Save as a Draft". This will hide the product from view but it is still in the system and can still appear on old POs.
Uploading a new file that is missing some products will force those "old" products to the top of your list.

You may watch this video for step by step instructions.