Hi Mark,
there’s a shortcode called portfolio under media tab. Open it, and it will ask you to install custom content portfolio plugin by Justin Tadlock (when you click on a link in shortcode, it’ll lead you directly to plugin installation page, and plugin will be listed first).
Install plugin, activate and add content to it. Then get back to shortcode and shortcode options will show when you open it again.
Regards,
Sinisa