How to obtain Ho Oh in Pokémon Colosseum

Here is the long-awaited video I was supposed to do but then life happened and yeah. Yes, I know the video cuts off sound because I forgot to turn it back on. No, I'm not fixing it. I already deleted the game lol
Short and simple list on what to do:
Purify all Shadow Mons (48 in total from main game to post-game)
Clear Mt Battle in story or post-game (Area 1-10)
Save and prepare team for MT Battle Vs 100
Enter Vs 100 from title screen main menu battle mode
Have fun!