You need two Game Boy Advances (Nintendo DS won't work), one e-Reader and a Game Boy Advance Link Cable. Then you put the e-Reader in one of the GBAs and a Pokémon Ruby, Sapphire or Emerald game in the other GBA. Then you connect the e-Reader to the other GBA with the Link Cable, swipe the Eon Ticket in the e-Reader and do something in the Pokémon game (not sure what; you might have to hold Start + Select when turning on the Pokémon Game instead of letting it start normally).