pleh, very easy
You just need to do a speedrun to complete 100% of Minecraft. Then, when you finish, you summon Herobrine (there are several videos on the internet on how to do this) and when summoned, ask permission to change the game mode to creative to get a frame pack for this portal, it's very easy. You'll have to fight him and that's it! Just enter creative.
I hope I helped hehe
