To create a folder and categorise your files, and share them easily, login to your dashboard then click on "all files" in the left sidebar to view your files.
From here, click "Create folder" on the top menu. This will open a modal where you can set the folder name. Enter it, then click "Create folder". You'll then be redirected to the newly created folder.
In this page you can upload files to the new folder, or drag & drop files into it from your "all files" view, or from other files.Folders are private by default, if you want to share them with other people, you must enable the "public" switch.