Step-2
Goto the "Additional Clocks" tab to set up an additional clock as shown, you will want to use "(UTC -06:00) Central Time (US & Canada)", and enter in a display name for to identify the clock. Then apply the changes.

To view the new clock just click on the clock in the right of the task-bar.

Optional:
Unless you have chosen to display the military time (24 hours) in the time and date settings, all clocks will read in the 12 hour AM/PM format.
Change time format.