How do you use stones on your Pokemon?
you go 2 your PC and put the stone that you want on it and if its the right stone it'll evolve
You go to your bag and select one of the evolution stones you have, then you select "Use" and the screen will go to your Pokemon party. Then you select the Pokemon that is able to use that particular stone to evolve. If you don't have any of the particular Pokemon that uses evolution stones to evolve, it won't work.