Hi!

So I created my own module and directly beneath my mymodule-folder are the files mymodule.links.action.yml and mymodule.routing.yml.

The problem I have is, that the actions-links are not shown in the browser.

mymodule.links.action.yml

mymodule.country_add:
  route_name: mymodule.country_add
  title: 'Add Country'
  appears_on:
    - entity.mymodule_country.collection
    - entity.mymodule_country.canonical

mymodule.routing.yml

entity.mymodule_country.canonical:
  path: '/mymodule_country/{mymodule_country}'
  defaults:
  # Calls the view controller, defined in the annotation of the country entity
    _entity_view: 'mymodule_country'
    _title: 'Country Content'
  requirements:
  # Calls the access controller of the entity, $operation 'view'
    _entity_access: 'mymodule_country.view'

entity.mymodule_country.collection:
  path: '/mymodule_country/list'
  defaults:
  # Calls the list controller, defined in the annotation of the country entity.
    _entity_list: 'mymodule_country'
    _title: 'Country List'
  requirements:
  # Checks for permission directly.
    _permission: 'view country entity'

mymodule.country_add:
  path: '/mymodule_country/add'
  defaults:
  # Calls the form.add controller, defined in the country entity.
    _entity_form: mymodule_country.add
    _title: 'Add Country'
  requirements:
    _entity_create_access: 'mymodule_country'

entity.mymodule_country.edit_form:
  path: '/mymodule_country/{mymodule_country}/edit'
  defaults:
  # Calls the form.edit controller, defined in the country entity.
    _entity_form: mymodule_country.edit
    _title: 'Edit Country'
  requirements:
    _entity_access: 'mymodule_country.edit'

entity.mymodule_country.delete_form:
  path: '/mymodule_continent/{mymodule_country}/delete'
  defaults:
    # Calls the form.delete controller, defined in the country entity.
    _entity_form: mymodule_country.delete
    _title: 'Delete Country'
  requirements:
    _entity_access: 'mymodule_country.delete'

These look fine for me..
One of the pages is the CountryListBuilder-Page:

<?php

namespace DrupalmymoduleEntityController;

use DrupalCoreEntityEntityInterface;
use DrupalCoreEntityEntityTypeInterface;
use DrupalCoreEntityEntityListBuilder;
use DrupalCoreEntityEntityStorageInterface;
use DrupalCoreRoutingUrlGeneratorInterface;
use DrupalCoreUrl;
use SymfonyComponentDependencyInjectionContainerInterface;

/**
 * Provides a list controller for mymodule entity.
 *
 * @ingroup mymodule
 */
class CountryListBuilder extends EntityListBuilder {

    /**
     * The url generator.
     *
     * @var DrupalCoreRoutingUrlGeneratorInterface
     */
    protected $urlGenerator;

    /**
     * {@inheritdoc}
     */
    public static function createInstance(ContainerInterface $container, EntityTypeInterface $entity_type) {
        return new static(
                $entity_type, $container->get('entity.manager')->getStorage($entity_type->id()), $container->get('url_generator')
        );
    }

    /**
     * Constructs a new CountryListBuilder object.
     *
     * @param DrupalCoreEntityEntityTypeInterface $entity_type
     *   The entity type definition.
     * @param DrupalCoreEntityEntityStorageInterface $storage
     *   The entity storage class.
     * @param DrupalCoreRoutingUrlGeneratorInterface $url_generator
     *   The url generator.
     */
    public function __construct(EntityTypeInterface $entity_type, EntityStorageInterface $storage, UrlGeneratorInterface $url_generator) {
        parent::__construct($entity_type, $storage);
        $this->urlGenerator = $url_generator;
    }

    /**
     * {@inheritdoc}
     *
     * We override ::render() so that we can add our own content above the table.
     * parent::render() is where EntityListBuilder creates the table using our
     * buildHeader() and buildRow() implementations.
     */
    public function render() {
        $build['table'] = parent::render();
        return $build;
    }

    /**
     * {@inheritdoc}
     *
     * Building the header and content lines for the country list.
     *
     * Calling the parent::buildHeader() adds a column for the possible actions
     * and inserts the 'edit' and 'delete' links as defined for the entity type.
     */
    public function buildHeader() {
        $header['country_id'] = $this->t('CountryID');
        $header['name'] = $this->t('Name');
        $header['continent_id'] = $this->t('Continent');
        $header['active'] = $this->t('Active');
        return $header + parent::buildHeader();
    }

    /**
     * {@inheritdoc}
     */
    public function buildRow(EntityInterface $entity) {
        /* @var $entity DrupalmymoduleEntityCountry */

        $ents = $entity->referencedEntities();
        $row['country_id'] = $entity->id();
        $row['name'] = $entity->link();
        foreach($ents as $ent){
            switch($ent->getEntityTypeId()){
                case "mymodule_continent":
                    $row['continent_id'] = Drupal::l(
                                    $ent->label(),
                                    Url::fromRoute('entity.mymodule_continent.canonical', array(
                                        'mymodule_continent' => $ent->id(),
                                            )
                                    )
                    );
                    break;
            }
        }
        $row['active'] = $entity->active->value;
        return $row + parent::buildRow($entity);
    }

}

Do I have to set/define anything anywhere to the mymodule.links.action.yml to work?
Or is there a better way to do this at all?