Umm... You don't in normal gameplay. Sorry!
In Meteor cave, you can get there after recruiting Lugia
i believe you have to befriend with lugia
go to silver trench first then get lugia to join your team then meteor cave will be unlocked
You find him in meteor cave after beating the elite four.
there's no cheat code after you recruit LUGIA from the SILVER TRENCH then meteor cave will open up...veronica
after Befriending Lugia Meteor cave will open up.
When you recruit Lugia in Silver Trench, the next dungeon will be Meteor Cave, which is the place you can recruit Deoxys.
After beating Team Rocket at the Goldenrod Radio Station and getting a Silver Feather and beating the Kimono Girls at Ecruteak City, go to the Whirl Islands and there will be a level 45 Lugia at the bottom of the cave. If you kill him, he does reappear.
when you Befriend Lugia Meteor cave with Deoxys will open up
you get it by entering meteor cave, which is found by blastoise the next morning after recruiting lugia
use waterfall in the cave and wander around, eventually you will find a certain trainer that you have registered in your pokenav. who??? well that is my little secret :) find out for yourself
WHich game are you talking about?!