Ok, well I'll start with EV's. Every Pokemon in the game will give off a certain type of EV. Say, a Zubat gives off 1 speed EV. IF you want your Pokemon to have a huigh speed, you battle only Zubat, which gives you the EV. The most you can gret are 252 EV's per stat, but there are ways of not having to beat 252 Zubat. Some Pokemon give higher EV's, Golbat give 2 speed EV's. The Macho Brace doubles the EV's you get, as does Pokerus.
IV's, Iv's are stats that are built into the Pokemon when its obtained. The maximum per stat is 31 IV's. Use an IV calculator to figure these out, its simple. if you want higher IV's, find Pokemon with ones that you want, and breed to get the right ones.