Update Tutorials intro page (#13280)

Author: nosolosw

docs/designers-developers/developers/tutorials/readme.md

@@ -1,6 +1,7 @@
 # Tutorials
 
-* If you want to learn more about block creation, the [Blocks Tutorial](../../../../docs/designers-developers/developers/tutorials/block-tutorial/readme.md) is the best place to start.
+* See the [Getting Started with JavaScript Tutorial](/docs/designers-developers/developers/tutorials/javascript/readme.md) to learn about how to use JavaScript within WordPress.
 
-* See the [Getting Started with JavaScript Tutorial](../../../../docs/designers-developers/developers/tutorials/javascript/readme.md) to learn about how to use JavaScript within WordPress.
+* The [Blocks Tutorial](/docs/designers-developers/developers/tutorials/block-tutorial/readme.md) is the best place to start to learn more about block creation.
 
+* The [Sidebar Tutorial](/docs/designers-developers/developers/tutorials/sidebar-tutorial/plugin-sidebar-0.md) will walk you through the steps of creating a sidebar to update data from the `post_meta` table.