thanks for that. I had done that already, but I'm coming from a KDE background, so
I was expecting a general "install theme" type option, which obviously isn't the case. Also, some of the themes I've downloaded don't all have the same components, so they aren't all listed under the various headings once I do unzip to /usr/share/themes.
Being new to the game, I just wanted to make sure I wasn't missing something obvious, it wouldn't be the first time....