Please help, how do you use mystery gift because I really want to get a..

Dude if you think you can get Deoxys by doing Mystery Gift well your wrong,it does not work.

Go into a pokemart and go to the desk and press a infront of the piece of paper and put in 'link together with all' then save and reset

Try the magic doors code at the AR cheat codes section and look for Birth Island.It works and it's totally works.And I caught Deoxys on my Fire Red.First turn on the code(you also need the Navel Rock/Birth Island Enabler code)go through any door and you should be at a harbour talk to the sailor there and he'll ask you if you want a ride.Your only option should be Vermillion.DON'T GO.If you go through the door you should end up at the harbour again.Now save your game and turn it off.Switch the gameboy back on with the AR in it.Turn off the code and take out the AR.Now go through that door you normally end up in the same place.Instead you should be on a triangular shaped island.Keep walking up and you should find a hovering black triangle.walk up to it and press A.It should move.The trick is to get to the triangle in the least amount of steps possible.At the last part of the puzzle,the triangle goes back to where it started.As before move up to it and press A.The triangle should tranform into Deoxys.It will walk towards you.Now prepare to battle Deoxys.It is on Lv.30but hard to catch.Do the Master Ball cheat NOT the all pokeballs cheat and voila you have Deoxys.To do it with mytery gift you have to go to the pokemon center in New York in the U.S.A.

Sorry, but you can't catch a Deoxys with mystry gift.