You don't need one of the 4 games in the intro. You can use any of the games listed here: https://3ds.hacks.guide/installing-boot9strap-(dsiware-game-injection-list)
Today I'll be showing you how to use SeedMiner to install Boot9Strap onto your 3DS with only one console. This is a relatively long process, so you'll need a lot of patience to get it finished. Make sure you have all the prerequisites at the beginning of the video, and if you don't, get them. You'll need all of them at one point. The advantage of this method is that it doesn't require anything physical other than 3DS (No magnet, no DS flashcart, no 2nd 3DS, etc). It's worth the increased time in my opinion.
Once you've finished everything in this video, refer to the readme.txt inside of the SeedMiner Package. It says to move on to TADpole: http://bit.ly/2nYgmLL
And then after you've completed this, start on section 5 of this page: http://bit.ly/2w3p1Cc
---LINKS & DOWNLOADS---
SeedMiner Package: http://bit.ly/2EVb0Ja
SeedMiner Package (Mirror): http://bit.ly/2BT400N
Python 2.7: http://bit.ly/2hYsuvu
SeedMiner GBAtemp thread: http://bit.ly/2Bo2xP5
TADpole: http://bit.ly/2nYgmLL
3ds.guide Page: http://bit.ly/2w3p1Cc
Thumbnail (by me): https://i.imgur.com/8raZuCS.png
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