This article provides direction on adding metrics to your summary panel. Adding metrics to and removing metrics from the Summary Metrics Panel is simple, provided that you've already been able to create the metrics in the system.
To add a metric to the panel:
Select the "+" sign at the end of the panel.
Figure 1. Add Metric Callout
Pick the metric from the drop-down list.
Figure 2. Selecting a Metric
Select Confirm to add the metric to the panel.
To remove the metric from the panel:
Select the three horizontal dots [...] on the top right corner of the metric.
Pick Remove from the drop-down menu.
If you need a metric that is not in the dropdown list of available metrics, follow the below link to know how to add metrics to your settings.