To attach files to an experiment, navigate to the Upload page by going to Actions>Upload>Upload more files.
From there, directly add files using the green Add files button, dragging and dropping files from your computer onto the drop area, or from a zip file using the Upload files using a zip file button on the page specific navigation bar. On the Experiment summary page, FCS files will automatically be added to the FCS files section and Non-FCS files will be listed under the Attachments section. You may find it useful to upload protocols, presentations, experiment layouts, and images related to the experiment in order to keep all relevant information backed up in one place. These attachments will also be visible to colleagues with whom you have chosen to share the experiment.
Other data types besides FCS can also be analyzed with a little bit of conversion work.