I want to change the emacs source code theme. Emacswiki says that I have to add the .el file to a directory in my download path, but what is my download path? And how do I access it?
Take a look at the Load Path page on emacswiki: http://www.emacswiki.org/emacs/LoadPath
Basically, you want to add a directory as follows:
(add-to-list 'load-path "~/emacs-load-path")