There is a keyword search box on the top right of Candex.
Whenever you run a search, results will always fill the right pane of your screen and are divided into three categories: Messages, Posts, and People. Click between them to see the results. The middle section will display conversations that contain your keyword from the names of people, companies and titles.
If you run a search from the Briefings page, the middle section will display ledgers that contain your keyword.