Themes do not change window appearance in Gnome

edit

Despite loading both Gnome Tweak Tool and the configuration tool, none of my themes will change the look of my windows. This could simply be a problem with me, as I've used Linux for all of two days; however, no matter what theme I have loaded, the options listed in the dropdown for "windows" in the tweak tool are the same as with the default theme. When I try to use the conf-tool, it simply loads Adwalla. I'm worried I'm missing something terribly obvious, so advice is welcome.

Thanks!