To create a new folder, select "Add Folder" in the files root or in any existing folder. You are not restricted when choosing a folder name. You can also choose to inherit rights (default: true) and copyright-data (default: false) from the parent folder.
Furthermore you can choose if the new folder should send notifications. This can be changed at a later point by editing the folder.
Tip
Disabling notifications can be useful if you want to prefill your folders before notifying your users. For example folders that contain a lot of images and should not send out a massive amount of notifications.