Are you in EdiZon? If so, click ZL so you can actually see the editable games, then locate your game. Click X to backup your game, after that click the -/Minus sign on the left joycon to edit the save.
I am in EdiZon, clicked on backed up my super dragon ball game, now the screen shows "Press - to load and edit your save file." But, I click the "-" button and nothing is happening