Downloaded -- now what

I've downloaded Omeka 1.5 onto my desktop. It shows like a folder on my Mac. But I don't know how to start using it. When I double click on the icons I see mini folders called plug-ins and admn and such. How does one begin?

Omeka is a web application, requiring a web server. What you downloaded is the application to upload to a server and set up.

To try out Omeka without a server, a free account on Omeka.net is probably your best bet.