Some operators of the TIS Editor require data from files, e.g., the Import text or CSV file 3.0 operator.
Right-click on the folder to which you want to add the file.
Choose "Add new file".
Data from the data file can be referenced by a data node by applying an operator like Import text or CSV file 3.0.
Similarly, it can be necessary to download a file.
Right-click on the file you want to download.
Choose "Download", download starts automatically.