Here is the help, how you can change the file in one task:
- Choose the right task and click on Edit.
- Click on "Add file"
- Click on the Drop here... section, browse the file on your local computer
- Click on the upload button (this uploads the file)
- Click on the done button (this saves the structure)
- Click once on the next button (this saves the step)
If you added the same file headers like you did before, you do not need to modify the Field mapping section, just click on the dashboard and hit once the run button.