diff --git a/web/modules/custom/yufu_concept/src/Plugin/rest/resource/AddConcept.php b/web/modules/custom/yufu_concept/src/Plugin/rest/resource/AddConcept.php
index 318568c..ce84378 100644
--- a/web/modules/custom/yufu_concept/src/Plugin/rest/resource/AddConcept.php
+++ b/web/modules/custom/yufu_concept/src/Plugin/rest/resource/AddConcept.php
@@ -117,6 +117,7 @@ class AddConcept extends ResourceBase {
       throw new MissingDataException('Title, uuid or text missing.');
     }
     $uid = $this->getUserIdByEmail($data['email'] ?? null);
+    $relatedConcepts = $this->parseReleatedConcepts($data['related_concepts'] ?? []);
     if ($concept = $this->getConceptFromUuid($data['uuid'])) {
       // Concept exists - create a new revision.
       $concept->setNewRevision(TRUE);
@@ -128,6 +129,7 @@ class AddConcept extends ResourceBase {
       $concept->moderation_state->target_id = 'draft';
       $concept->set('status', 0);
       $concept->setUnpublished();
+      $concept->set('field_related_concept', $relatedConcepts);
       $concept->save();
       $this->logger->notice('New concept @title revision @revid created by uid @uid.', [
         '@title' => $concept->getTitle(),
@@ -149,6 +151,7 @@ class AddConcept extends ResourceBase {
       // @TODO Check language and add set it on concept if exists.
       /** @var \Drupal\node\Entity\NodeInterface $concept */
       $concept = $this->entityTypeManager->getStorage('node')->create($concept);
+      $concept->set('field_related_concept', $relatedConcepts);
       $concept->save();
       $this->logger->log(LogLevel::NOTICE, $this->t('Creating concept: @title', [
         '@title' => $concept->getTitle(),
@@ -219,4 +222,28 @@ class AddConcept extends ResourceBase {
     return $new_user->id();
   }
 
+  /**
+   * Parses the data from post request.
+   *
+   * @param array|null $parseReleatedConcepts
+   *   Data provided by post request.
+   *
+   * @return array
+   *   Array of concept nodes in format suitable to set on node.
+   */
+  protected function parseReleatedConcepts(?array $relatedConcepts): array {
+    // @TODO Specify how array of related concepts comes from the fe request.
+    // We can do some quick check if related concepts exists.
+    $result = [];
+    if ($relatedConcepts) {
+      foreach ($relatedConcepts as $concept) {
+        // @TODO Validate concept and get its id.
+        $result[] = [
+          'target_id' => $conceptId,
+        ];
+      }
+    }
+    return $result;
+  }
+
 }