A Combo chart is used to display a trend line or average line along with the metric values. It can also be used to display multiple metrics using a combination of line & bar charts within a single chart
To create a Combo chart
Ensure you are on a dashboard (not created from a template).
Click on the menu located in the top-right corner of the screen.
Select 'Add Visualization' -> 'Create new gadget.'
In the 'Create new gadget' window, select 'Combo' as the gadget type.
Enter a name for the Combo chart gadget.
To display an existing metric, click on 'Add Metric' and choose from the list of pre-defined metrics.
Alternatively, you can create a new metric specifically for this gadget by clicking on 'Create Single-use Metric.'
Choose a dimension for the X-axis. In the provided example, we use 'date.'
Plotting trend or average
To plot the trend or average for the selected metric, toggle on the 'Plot average' or 'Plot trend' setting on the metric
Displaying multiple metrics using a combination of line & bar charts
Add a second metric to the gadget and set the type to 'line'.
If the scales of the chosen metrics vary greatly, toggle on the 'Separate Y Axis' & 'Opposite' settings on the metric to bring it into view.
Set the default date range for your Combo chart using the date picker
If you want to set up a report to drill down to from this gadget, select a report from the dropdown located in the top-right corner.
Once you've configured the default date scope, run time filters & scope filters, click 'Save'.
The Combo chart gadget will be added to the bottom of your report. Scroll down if needed to re-position and resize the gadget as required.