1) Choose a better topic title; nobody cares whether you're a newbie or not (besides, that'll become clear really quickly
). "Can I use the Juno as a controller?" would've been better.
2) Roland has a whole load of synthesizers called "Juno" - which one? Juno-G? Juno-DI? Juno-60? Alpha Juno 2? Don't make us guess.
3) Anything with MIDI can be used as a controller (it just requires an USB MIDI interface). Anything with USB nowadays can (almost always) be used as a controller. It's just that controllers have lots of sliders, knobs and drumpads, and the Juno G has 6 knobs and that's it. So, yes, you can, but it's not as ideal as a dedicated controller is, because those easily allow you to change the task of the sliders and knobs, and you get a lot more of 'm.