Plugin installation.

Hi, I'm probably missing something very basic, but I'm having trouble installing this plugin.

I've followed this guide: http://wiki.jetbrains.net/intellij/Getting_started_with_La_Clojure and I've downloaded and installed the plugin fine, however after installing the plugin and going to open the project, I cannot open .clj in the open project files screen. When I go to the plugins menu again, La Clojure is located there with a tick next to it showing it is enabled, and on the right it says it is version 0.7.61.

Apologies if this is something very basic, but I'm unsure as to what is wrong. I'm using Intellij IDEA 13.0.2 community edition build #IC-113.696


Thanks.