It includes repository filtering by annotations using
@EnableJpaRepositories(includeFilters = ...)
It also includes Liquibase configuration for one of the databases
Just replace ${db.primary.}/${db.secondary.} in application.yml with your databases credentials.
Here you can see how to use annotation filters for your repositories: example
If you want mark your method as @Transactional you need to specify proper transactionManager (based on the db you are calling), for example:
@Transactional("primaryDataBaseTransactionManager")
public void deleteById(UUID id) {
primaryDBEntityRepository.deleteById(id);
}