What coding do I need to control characters in a game app?
Welcome to the forums. By control do you mean movement ? if so check out the character controller in the standard assets that can be installed with Unity. The assets package comes with a third person and first person controller. Also the asset store has a couple freebie controllers.
As BlackMantis says, do check out the Unity Asset Store. There are a number of things there that you can try out and play around with to see how they work.
However, do also be sure to take the time to follow through some decent tutorials to get you started. 
Thank you!! Are you in Phoenix, by any chance? I would be happy to work with someone with experience in this.
Hi Unitylanguages. I can’t speak for BlackMantis, of course, but for myself, no. I’m in the UK- it’s a long walk to Phoenix.
However, I think you’ll find plenty of support generally on these forums. Just be sure to go through some tutorials to find your feet a little. Then try something out (however small), and if you get stuck with it, don’t forget to show what you have tried and people will be able to help you out easily enough.
Actually, thinking about it, Unity hold events as well from time to time. Maybe you could check for one near you?