What
See screenshot where metrics has 4 Applications (1 per sub-service), but Keycloak has 1 Appliation with the 2 sub-services (keycloak & postgres) in it.
This would look a lot less confusing if all 4 metrics parts showed up in 1 'Metrics' application in this screen

How
See how labels on services/deployments need to be aligned to do Application grouping.
Keycloak is a good example of this.