I have a 2002 Toytota Highlander Limited with 4WD, only I cant figure out how the 4WD works. How do I turn it on? Is it as simple as hitting this ETC/SNOW button, or is there more to it than that? Any help would be appreciated...

Have you checked your owners manual?

I think those are AWD (all wheel drive). There is no option for turning it on or off. Its on all the time.

It's on all the time, read owner's manual. Use the snow button to reduce wheelspin when there's a lot of snow.