Have a look at this article on structure and naming before creating a folder.
How to create a Folder:
- Right click in your Flipbook tree (Alternatively left click the tree dots found on the right or use the New folder button).
- In the drop-down, select "New Folder".
- Name your Folder.
- Chose location.
- Click create.
But how do I move my Flipbook you may ask :D Click here for an article on that.
Remember, as mentioned in the top, moving Flipbooks will change the structure of your Flipbook URLs.