You can categorize your artwork by using the Albums feature.
To create an album, first navigate to your Portfolio Manager from your Avatar menu.
[Image removed during migration — original screenshot was hosted on the old support platform and is no longer accessible. Needs to be re-captured/re-uploaded.]
On the left side of the Portfolio Manager page, you have the option to create and manage albums. Click on "Create new album" and name it. If you have a Premium account, you will have the option to select its visibility. Click save once you are done.
Once you have created your Album, you can just click and drag a Project into the Album folder.