There can only be one Cloud Firestore instance associated with a single project. The Datastore instance is automatically created when you enable the API:
There can only be one Datastore instance associated with a single project. The Cloud Firestore in Datastore instance is automatically created when you enable the API:
gcloud services enable datastore.googleapis.com
Because Cloud Firestore is a NoSQL database, you do not need to explicitly create tables, define data schema, etc. Simply use the API to store new documents, and perform CRUD operations.
Spring Data Datastore
The easiest way to access Datastore is using Spring Cloud GCP's Spring Data Datastore starter. This starter provides full Spring Data support for Datastore while implementing idiomatic access patterns.
There is no explicit configuration required if you use the automatic authentication and project ID detection. I.e., if you already logged in locally with gcloud command line, then it'll automatically use Datastore from the project you configured in gcloud.
Notice that there is no explicit configuration for username/password. Cloud Firestore authentication uses the GCP credential (either your user credential, or Service Account credential), and authorization is configured via Identity Access Management (IAM).