Dial charts available only in dashboards. Steps to create dashboard with single dial chart:
1. Right-click on "Dashboards" tree, select "Create dashboard".
2. Open properties for new dashboard object.
3. Open "Dashboard Elements" page.
4. Press "Add" button, select "Dial chart" as element type.
5. Double click on new element in list, dashboard element properties dialog will open.
6. Open "Data Sources" page.
7. Press "Add" to add DCI you want to show.
8. Open "Dial Chart" page.
9. Enter desired values for maximum value and values for red and yellow zones.
10. Press OK to close dashboard element properties.
11. Press OK to close dashboard properties.
12. Double click on dashboard object - you should see dashboard with single dial chart element.
You can also see this screencast on dashboard creation: https://www.youtube.com/watch?v=ZfJQiUIDHY4