Sounds like you only installed its Joomla bot. Download CB AntiSpam from its products page below, which will include all of CB AntiSpam (including its CB plugin).
www.joomlapolis.com/addons/cb-antispam
You can also download its preset below, which also contains all of CB AntiSpam.
www.joomlapolis.com/downloads/presets
Alternatively within CB > Plugin Management > Install New Plugin you can install its CB plugin under the "Install from Web" tab.