How to install themes on MATE?

[xenopeek]

So I just got linux mint 13, and I downloaded a theme, but I don't know how to install it. I thought there was some sort of theme manager but I cant find that in my computer or on the Software Manager, and since this is my first offical day with linux im stilll a newb :3 sorry

[xenopeek]

Depends a bit on which edition of Linux Mint you downloaded. Did you download the Cinnamon, MATE, Xfce or KDE edition?

[Joe3000]

I have MATE

[Joe3000]

But i think im on the verge of figuring it out, I found the "theme manager" but its called appearance preferences but when i isntalled the theme and changed it, it made verything blocky like an old windows computer. It also says at the bottom, "This theme will not look as intended because the required GTK+ theme 'Ambiance" is not installed" so now im trying to figure out how to install Ambiance....