How to insert a custom configMap in Core Members

I deployed Neo4j 3.5 in a kubernetes cluster by using an helm chart.
I would like to enter a configuration for core cluster members using a custom configMap.

Here is my YAML file for helm:

acceptLicenseAgreement: "yes"

neo4jPassword: "..."
imageTag: 3.5.9-enterprise

# Cores
	configMap: <My custom configMap>

What are the steps to follow to create and insert my custom configMap?