To see project files - mouse over the project’s avatar and choose the “Files” link. If the owner’s plan allows file uploading you can do that by clicking on the “upload” button or dragging a file from your hard drive to the “drag file here” area. You can create folders within folders, within folders, in your project’s files.

If you upload a file directly to a project’s task or to a comment inside the project’s task - a folder with those files named after this task is created magically by our file fairy.