Take a look at this tutorial.
click here
I'm listening to it now as I do other things online. It seems professional and easy to understand.
You may need to stop and rewind here and there.
If you don't like it, I'll look for another.
ps
I liked it. His voice is a bit robot like but that's fine. The author made 2 more for your phone, one about closing apps and the other about doing a reset.