3rd Gen Need Help With EV Training

[Tyranitar042]

Im training my bulbasaur in firered for speed and special attck and i just beat a couple of gengar on my vba (learning to ev train) and gengar gives 3 to special attack right and i strted battling gengar and got 12 evs to special attack but it didnt add on when it leveled up? does it take a while for it to work or what? Do you get ev's when you enter the battle or when you get the exp from the pokemon? can anyone help please i wanna know how to ev train.

 

[Ivysaur]

Here you'll have pretty much everything you need.

 

[Tyranitar042]

thanks thats all i needed