There are reasons why we all recommend using the official guide over other written guides or
even worse YouTube videos.
They are often incomplete, omit important steps and are outdated quickly. Also note that it is hard to help since nobody involved in 3DS assistance on GBAtemp is able to keep track of all video guides out there. In addition to that many guides tend to
"simplify" the process by providing some
"convenient" all-in-one-package containing the necessary downloads where one can never be sure that the contents of that package is ever updated.
It can't be that hard to find a computer that is able to open the page even if you got some error on your computer previously. 3ds.hacks.guide is currently up and running fine.
===========
Anyway:
Possible reasons for Luma chainloader not appearing:
* No payloads in SD:/luma/payloads
* Only one payload in SD:/luma/payloads
Because of a known bug current stable release of GodMode9 fails to load from Luma3DS v10.2 chainloader when only one payload is present. GodMode9 might start without backlight. Closing and opening the 3DS might turn backlight on. A second, dummy firm (named "DO_NOT_LAUNCH.FIRM") is used to force the chainloading selection menu appearing.
* B9S is not yet installed. Try bringing up Luma3DS settings by holding (Select) on power on to ensure B9S is present.
* Defective (Start) button. Make sure the button works.
Since the ASK!-section does not allow embedding videos while the editor replaces any YouTube-Link with the "[MEDIA=youtube]", I try linking the video in question
with a link name instead (for reference).