Here is how you can edit the Metadata associated with a file:

1. From My Files navigate until the file you want to edit is displayed in the list
2. Click on the ellipses (...) to the right of the file you wish to edit
3. Choose the Metadata option from the drop down menu
4. You will now be in the Metadata editing screen
5. Make changes to the Metadata associated with this file
6. Click Update to save your changes