Please open the CS app-->bottom "Docs"-->tap the folder icon on top left to create. 

After the folder is created, you can take pictures or import images and save docs into it directly.

If you want to move existing docs to this folder, please select docs on Docs page-->bottom "Move/Copy"-->"Move"-->select the folder. 

Please note the folders won't be shown under the tag. If you're unable to view the folders, please tap "All Docs" on top right to find them.