📝 Add tutorial for rig stacking

Author: SnaveSutit

src/routes/docs/[...5]resources/[...2]tutorials/stacking-rigs/+page.md

@@ -0,0 +1,60 @@
+---
+title: Stacking Rigs
+description: Learn how to stack rigs on top of each other to create dynamic models.
+---
+
+# {$frontmatter.title}
+
+{$frontmatter.description}
+
+## Introduction
+
+"Stacking" is a term used to describe the process of mounting multiple entities on top of eachother.
+
+Using [Locators](/docs/the-blueprint-format/locators) and their [Use Entity](/docs/the-blueprint-format/locators#use-entity) and [On-Summon Commands](/docs/the-blueprint-format/locators#on-summon-commands) properties, you can stack multiple rigs on top of each other to add dynamic parts to your model.
+
+## Tutorial
+
+Let's take an existing rig (`body`) and stack our head rig (`head`) on top of it.
+
+1. Inside of your `body` rig, create a new [Locator](/docs/the-blueprint-format/locators) named `head_locator`. Position this Locator where you want the head to be mounted.
+2. Open up `head_locator`'s config and configure the following properties:
+
+    1. Enable `Use Entity`
+    2. Set the `Entity Type` to `minecraft:item_display`
+    3. Set `On-Summon Commands` to
+
+        ```rust
+        	function animated_java:head/summon {args:{}}
+        	ride @n[type=item_frame,tag=aj.head.root] mount @s
+        ```
+
+3. Save and [Export](/docs/getting-started/exporting-your-blueprint) both rigs.
+4. In Minecraft, reload your Data Pack and Resource Pack.
+5. Run `/execute rotated 0 0 run function animated_java:body/summon {args: {}}` to summon your body rig.
+6. You should see the head rig mounted on top of the body rig.
+
+From here, you can use your own commands to adjust the `head` rig's rotation as needed.
+
+:::admonition type=info title=Example
+To match the `head` rig's rotation to the `head_locator`'s rotation, you can add the following command to the `head_locator`'s [On Tick Commands](/docs/the-blueprint-format/locators#on-tick-commands):
+
+```rust"
+rotate @s ~ ~
+```
+
+Or, if you wanted it to face the opposite direction:
+
+```rust"
+rotate @s ~180 ~
+```
+
+:::
+
+## Common Issues
+
+### The `head` rig falls behind the `body` rig when moving.
+
+1. Open up the exported Data Pack, and locate `datapack/animated_java/data/animated_java/tags/function/global/root/on_tick.json`.
+2. Make sure the `head` rig's `on_tick` function is listed _after_ the `body` rig's `on_tick` function.
+3. You can manually reorder the functions in this file, or rename the `head` rig to `z_head` to force it to be listed last.