Visit the downloads section of webdna.us to find WebDNA fcgi suitable for your server.
You will need to install version 8.5 or later
Download a copy of WebDNA eCom core files
Download WebDNA eComInstall and configure WebDNA as per the instructions: WebDNA Downloads
Configure WebDNA to use .dnalib
FTP to the root of your site and upload the contents of the WebDNA eCom directory
http://yoursite.com/admin
You are now ready to add content to your store