Homebrew Custom HBL for PS1/N64/GC games

[gregmurf]

Hi all,
i just read this guide to play GC/PS1/N64 games, and the firts spoiler for the AIO section is:
1) Open this Google Drive link:
(REMOVED, make your own Homebrew Channel inject with the Wii VC inject script. I can't help since its considered copyright)
So i read the "Wii VC inject script" guide who can create custom HBL, but i dont know:
- Why i have to create a CHBL ?
- What does this CHBL have to include ?

Sorry, question from a noob...