[Akatsuki92]

The circled part of the image how to know what to put for the ev training?  I'm really confused about how to ev train but I need to start doing this?

1. What Natures are the best on pokemon and how do you know it is the best for that pokemon?

2. Does the Pokedex matter on what Stats, Iv's and Ev's or how much you put into Attack, Defense, Speed ect?

3. How do you know  the right Abilities for that pokemon are?

4.  Do you put the Protein, Iron, HP Up, Calcium, Zinc, and Carbos before you do Ev's and Iv's Training with Mach Brace or is there a certain point you use those?