The SAVE AND EXIT button applies all changes made in the editor, closes the editor, and you will return Halo Reports.
The SAVE AND CONTINUE button applies the changes made in the editor and keeps you in the editor to continue making changes to the imported dataset.
The DISCARD CHANGES button cancels any changes that were done after the last save was made, closes the editor, and you return to Halo Reports.
Ctrl+S keyboard shortcut can be used to save the applied changes and it will keep you in the editor mode to continue making changes to the imported dataset.