I have an idea I want to write as an app for use on a tablet or possibly a smart phone. I am a retired coder and still write code, but have not paid attention to the whole app thing. Is there one good website that can get me started and describes what the hell to do well enough for an old fart like me?? Much of the data will be on the server, some will have to be stored locally by the user but it will be minimal. It is basically a specialty calculator that requires historic weather data.