help with hacking pokemon emerals

I am working on a pokemon emerald hack. I wan't to make several brand new fresh towns citys caves routs eta. I need help adding a brand new pokemon center and pokemon mart. I don't know hop to add sprites. I also need help placing pick-up items (items you find). I know how to build a new mart and pokemon center but I don't know how to make a nurse joy heal pokemon. I also can't make a guy to buy stuff from the shop I made. also all the areas I made I can't run or bike I wan't to change it so you can run and bike.