Improve introduction to 3D for beginners

tutorials/editor/default_key_mapping.rst

@@ -140,6 +140,8 @@ General Editor Actions
 | Clear Pose                   | :kbd:`Shift + K`        | :kbd:`Shift + K`       | ``canvas_item_editor/anim_clear_pose``                 |
 +------------------------------+-------------------------+------------------------+--------------------------------------------------------+
 
+.. _doc_default_key_mapping_shortcuts_spatial_editor:
+
 3D / Spatial Editor
 -------------------
 

tutorials/editor/index.rst

@@ -1,6 +1,8 @@
 :allow_comments: False
 :article_outdated: True
 
+.. _doc_editor_introduction:
+
 Editor introduction
 ===================
 

tutorials/editor/project_manager.rst

@@ -61,6 +61,8 @@ When the folder path is correct, you'll see a green checkmark.
 
 .. image:: img/editor_ui_intro_project_manager_09.webp
 
+.. _doc_project_manager_downloading_demos:
+
 Downloading demos and templates
 -------------------------------