I saved before Xurkitree.
1.I click A to start the battle
3.I press start/select (I use a rubber band to hold down L and R)
4.I go through the dusk mane necrozma thing and press a to continue
I just close my 3DS if I am going to come back to it soon and I press home menu, close the game, and press the power button to turn the 3DS off.
Am I doing it all correctly?