So, I'll try and explain this as best I can, but you can always google it for a better explaination.
IV's are know as inherent values, they're are hidden numbers that range from 1- 31 for each of your pokemons stats (Attack, Sp. Attack, Defense, Sp. Defense, Speed, HP) and basically they determine how high your pokemon can get in each stat. They also determine the type and power of your pokemon's hidden power. You can also only have 255 of an EV in any one stat. Though 252 is more prefered as the extra 3 EV's from 255 will have no benefit on the stat.
Hope this helps. If you have any more in depth questions, feel free to ask.
Now IV's can be breed for, as when you have two pokemon breeding, the resulting offspring with have some IV's from it's parents. You can go on google and find a more detailed explanation of how it works.
Now EV's are known as Effort Values and you have 510 of them to 'award' to each of your pokemon. Every pokemon has a specific EV that it gives when it is fainted. For example Pidgey's give 1 Speed EV. So if your say Alakazam fainted a Pidgey it would gain 1 Speed EV. For every 4 EV's of a stat your earn, you'll get +1 to that stat the next time you level up.