Player since 2010 and I have never jungled before, how to start?

As titles say, ive been playing on and off since s2, and Ive played every role at a diamond lvl except for jungle. I have really no clue about timers, path, objective control and somehow wonder how could enemy jungler out cs and out gank my junglers.

I wanna give it a try, where could I start? Who to watch, what to focus on?