I have never done this with Android OS, just the Arduino IDE for windows 7. However, I know someone compiled the Arduino IDE for Android and it is available on the play store. I would download it from there (just search in apps for arduino). I suspect it has some example code and tutorials to get you started. If you have windows, you might want to start from there.
I have an S4 mini and it does not allow USB host controller or whatever the drivers are that you need to connect USB devices to the phone without rooting.