Hi, tdOtijunior,
There is no need to put salt into your tank for Molly. They do fine in freshwater.
Consider you plan to add plants, plants hate salt although they can tolerate slight salt concentration.
As for what food to feed them, they aren't picky eaters from what I know. You can try any high quality flake or pellets as stamp food. I recommend Omega One and New Life Spectrum. They are the best of the best for stamp food. Pellets might be superior to flakes due to their nutrition do not dissolve into the water as quickly once you throw them into the tank, and fish can easily eat them whole without polluting the water.
This article talks about the high quality fish food. You really only need just one stamp food, and then feed 1 or 2 supplement treats once or twice a week. http://petskeepersguide.com/best-food-to...sh-colors/
For plants, if you haven't had a lot of experience with them, I suggest you start with hardy plants such as Java Moss, Java Fern, and Anubia. They are easy to take care off. To have plants, you need to have good lights. I use T5HO lights in my own aquarium.
