diff --git a/src/Facades/MoodleGroup.php b/src/Facades/MoodleGroup.php
index bdcfee2..5ff9797 100644
--- a/src/Facades/MoodleGroup.php
+++ b/src/Facades/MoodleGroup.php
@@ -15,6 +15,9 @@
  * @method static GroupResourceCollection getCourseGroups(int $moodleCourseId)
  * @method static UserResourceCollection getGroupMembers(int $moodleGroupId)
  * @method static GroupResourceCollection delete(array $ids = [])
+ * @method static mixed create()
+ * @method static mixed addMember()
+ * @method static mixed removeMember()
  */
 class MoodleGroup extends Facade
 {
diff --git a/src/Services/GroupService.php b/src/Services/GroupService.php
index dba45bc..cfa04ea 100644
--- a/src/Services/GroupService.php
+++ b/src/Services/GroupService.php
@@ -11,7 +11,7 @@ class GroupService extends Service
 {
     public function getById(int $moodleGroupId): GroupResource
     {
-        $arguments = ['groupids' => $moodleGroupId];
+        $arguments = ['groupids' => [$moodleGroupId]];
 
         $response = $this->sendRequest('core_group_get_groups', $arguments);
 
@@ -41,4 +41,16 @@ public function delete(array $ids = []): GroupResourceCollection
 
         return GroupResourceCollection::make($response);
     }
+
+    public function create() {
+        // TODO
+    }
+
+    public function addMember() {
+        // TODO
+    }
+
+    public function removeMember() {
+        // TODO
+    }
 }