Classipress is a wordpress theme and if you need another theme for your directory you need another instance of Wordpress for it too.
I am looking to create a website with the ability to have a directory and classified ads listing. I have been having a read and from what I can see if I purchase Classipress which is a theme I would need to create a subdomain to add the other theme into? But essentially this would mean that I have the directory and classifieds working alongside on the same site?
If you can follow instructions you can definitely install Wordpress in less time. Some host's already include a built-in installer that you can use.
You may visit the Wordpress site
http://wordpress.org/ for the basics on setting it up.
A basic knowledge in html, php, css and java script will come handy if you need to modify the theme.
And as a bit of a wordpress novice is this likely to be too much for me to be able to do? lol
