First, defeat all of the gym leaders and elite four. Then, defeat the hoenn and sinnoh battle frontiers. Walk around on any map until you find a legendary pokemon. Done.
If you mean when you start a battle its the pokemons cry
you will find feebas in the water of grass maps in pokemon vortex
just battle with a Pokemon
Acshoin replay
you will find beldum in the cave
You find him in map 18.
In the grass area
none
You'll find it in the electric maps
you cant. Lumineon is a 4th generation pokemon.
you look around
next to grass maps
Go to a map, walk around until you find a Pokemon, and catch it.