Pokemon The Eevee chronicles

I have no idea how to make a hack. ANd wouldn't begin to know which of the many threads on this site to look into first. So here is my idea and if any one wants to help me make it, I would aprecite it.

Basic story. You start your adventure (just like all other pokemon games). The professor offers you one of the three starters. You pick your favorite. Then he tells you to visit your mother and say goodbye before you leave. Your mother tells you that she once went on a similar journey. Then hands you an eevee. Then each gym has one form of eevee in their line up.

Gym Leader Brock - which ever one Koga doesn't use ( or a new one can be made)
Gym Leader Misty - Vaporeon
Gym Leader Surge - Jolteon
Gym Leader Erika - Leafeon
Gym Leader Koga - Espeon or Sylveon (not sure if either ar psychic)
Gym Leader Sabrina - Umbereon
Gym Leader Blaine - Flareon
Gym Leader Giovanni - Glaceon

Then after you beat said gym leader, in addition to badge and tm, they hand over the stone needed to get your eevee to evole into their form.

Moon Stone = Umberon
Sun Stone = Espeon
Fire Stone = Flareon
Water Stone = Vaporeon
Thunder Stone = Jolteon
Leaf Stone = Leafeon
Dusk Stone = Glaceon
Shiny Stone = Sylveon

And yes I know that it would need to be coded in a way to make those last three work.

okay I have found the tutoritals explaining how to do some of it. I would still like help though

lance_the_dragon said:

Gym Leader Brock - which ever one Koga doesn't use ( or a new one can be made)
Gym Leader Misty - Vaporeon
Gym Leader Surge - Jolteon
Gym Leader Erika - Leafeon
Gym Leader Koga - Espeon or Sylveon (not sure if either ar psychic)
Gym Leader Sabrina - Umbereon
Gym Leader Blaine - Flareon
Gym Leader Giovanni - Glaceon

Click to expand...

I know now that Epeon is psychic. and all of them can learn toxic, thus Umbereon can work for the posion gym. How do I make a rock type?