Do purchased themes need to be fully built from the ground up? Really naïve newbie question....

I am brand new to Drupal after working in Wordpress for quite a while.  We bought a custom agricultural theme for $75 - it looked perfect for my project at work.  The sample had all the right stuff with content placed in areas I can customize to my project.

However, now that I have downloaded it, it is just "bare bones."  The structure for the content and images is nowhere to be found.  The drop-down menu isn't horizontal, the whole structure is absent. I thought this would be easier.  Do I have to build everything in Dreamweaver? Did I miss something? Are the themes merely "suggested formats?"
where did you buy the theme from? Do they provide installation instructions or usage instructions? Did it ship with any additional modules to enable configuration?

A theme is basically styled blocks, views, nodes, regions. You need to place your content into Regions of the theme for it to show up like their example.