[Dan Waxman]

To reiterate what others have said, I would definitely focus on teaching Java before you focus on any robotics concepts; it would be very difficult to read or write a book in Spanish if you don't speak any. After you get your students started on Java to a point where they can coherently read through other's code, then the FRC concepts come easy. There's very little to program that's difficult in FRC, and odds are if it's difficult, there's been a tool made to make it easier. So I'd just drive home that fundamentals are key.

As for how to teach, there's multiple approaches. Two mentioned before are codeacademy, which is a great resource, or academic class available online. Both of these are great options. Personally, the way I'd do it would be to teach during team meetings, and then supplement that learning with further learning online that you plan out, as well as incorporating challenges to mix in (codewars.com is awesome for this). Any questions feel free to PM me.