Its like what everybody says. For any type of hacking no matter the console do not follow video
tutorials. Always use the official websites which provide pictures and all that crud.
For example...the 3DSs hacking site is
https://3ds.guide
Only use that.
Now i was lucky. I'm more of a visual learner so i watched a video when i CFW'd my first 3DS using SoundHax as the gateway to the Homebrew Launcher. The video was not bad and i understood everything. Some videos (kind of like yours) can be bad or offer files from their own system which if you put on yours will brick it.
Some people told me it was stupid but look at me now. My 3DS is still fine to this day. I even got my new model 3DS i bought this year CFW'd without a video
tutorial due to me learning how to do it. I just took my old CFW'd 3DS and transferred it over to my new 3DS.