Ev training at first sounds very confusing and crazy but when you get down it's fairly easy. Example: Each pokemon has 6 stats Hp. Attack. Defense. Sp. Attack. Sp.Defense. Speed. Each pokemon has a stat that they are really strong at. An Example of that is Geodude, they have great Defense power, so every time you kill one Geodude you're pokemon gets +1 to Defense. There are 510 Ev points that you're pokemon can have, so that means you can have 255 Ev points on 2 stats of you're liking. That would mean you would have to kill 255 Geodudes to get you're defense stat into tip top shape, but you don't have to do that since there are items like Macho Brace which double the Ev points you get. As well as the pokerus which you probably heard of, that also makes Ev training a hell of a lot faster. Hope this helps if you need any more help let me know ^.^