Change cinnamon theme from Cinnamon Spices site to local one

I cannot seem to get a handle on changing my cinnamon theme from those already on the Cinnamon Spices site to one that I have downloaded. I loaded it into /usr/share/themes and it would not show up. I put the theme into ~/.themes and it also didn't show. I also noticed that /usr/share/theme contains several themes that LinuxMint put in /usr/share/themes and they don't show up.
I'm sure I am missing a minor factor somewhere, but I cant find it.