add field to bundle through hook_entity_bundle_field_info I am trying to add two fields to one of the node bundles.

I define the fields in this function:

function concertbeheer_entity_bundle_field_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type, $bundle, array $base_field_definitions){
    if($entity_type-&gt;id()=="node" &amp;&amp; $bundle == "concert")
    {
        $concert_fields['laatste_uitvoering'] = \Drupal\Core\Field\BaseFieldDefinition::create('datetime')
                -&gt;setLabel('Laatste uitvoering')
                -&gt;setRequired(TRUE)
                -&gt;setDisplayConfigurable('view', TRUE)
                -&gt;setDisplayConfigurable('form', FALSE)
                -&gt;setDisplayOptions('view', array(
                    'label'=&gt;'inline',
                    'type' =&gt; 'datetime_plain',
                    'weight' =&gt; '999',
                ));
        $concert_fields['eerste_uitvoering'] = \Drupal\Core\Field\BaseFieldDefinition::create('datetime')
                -&gt;setLabel('Eerste uitvoering')
                -&gt;setRequired(TRUE)
                -&gt;setDisplayConfigurable('view', TRUE)
                -&gt;setDisplayConfigurable('form', FALSE)
                -&gt;setDisplayOptions('view', array(
                    'label'=&gt;'inline',
                    'type' =&gt; 'datetime_plain',
                    'weight' =&gt; '999',
                ));

        return $concert_fields;

    }


}


but the documentation on https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Entity%21entity.api.php/function/hook_entity_bundle_field_info/8.2.x says I also need to provide a fieldStorageDefinition through hook_entity_field_storage_info() 

I can actually configure the visibility of the fields but when I save something to them it isn't saved in DB. Probably because of the lack of a FieldStorageDefinition

But I don't know how to get started on that and, as usual, there seems to be no documentation available on how to do it
This code example would set up a basic storage definition:

function mymodule_entity_field_storage_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type) {
  if ($entity_type-&gt;id() == 'node') {
    $definitions['my_bundle_field'] = \Drupal\Core\Field\BaseFieldDefinition::create('string')
      -&gt;setName('my_bundle_field')
      -&gt;setLabel(t('My new bundle field'))
      -&gt;setTargetEntityTypeId($entity_type-&gt;id());
    return $definitions;
  }
}


You can look up examples in field.storage.*.yml files from a config export.

If you don't find the right examples there, you can configure a field in UI and then export the storage of this field to get a blueprint for the storage definition you need in this hook.