When you create a new folder using the normal + button (the one where you can also create scripts and other files) you can select into which folder the new folder should go, and you can enter a name at the top.
When you create a new folder from the edit view (press Edit on the file list, then select the "new folder" icon in the bottom toolbar) you can enter a name, but it is always created in the current folder.
If you want to rename a folder after you've created it, go into the folder in the file list, press Edit, then select the "rename" icon next to the folder title in the top toolbar.