How do I get it? (Even with school starting TOMORROW and the fact I only have one modded 3DS)

OK so I found out how to get it but I'm confused, is replacing the boot.firm file optional? And will it work when I already have Pretendo installed?

Just got it, funilly enough a few days ago I was thinking about Pretendo not having ACNL support, so good to know there is something else that brings it back! Thanks :)

I got it a few days ago but due to OCD I'm not using it much.