If a file has been created outside of Code Co-op's control and saved within a project tree, you can add it to the project. From within the Files area, select the file/s and click Add To Project from the toolbar as shown. Other members of the team will learn about this addition after you make your next check-in.
You may also add a whole folder to the project. You will be given a choice as to which files in that folder (and its sub-folders) to add to the project. You'll be able to select groups of files to be added either by extension or individually.
See also: