chore: update build from source files (#11)

Author: nmerget

docs/documentation/building-from-source/index.md

@@ -8,6 +8,37 @@ The following runtimes are available:
 - [`JavaScriptCore`](javascript-core.md) is the built-in JavaScript engine for WebKit and bundled with macOS/iOS.
 - [`Web`](web.md) is only suitable when building for Web. All scripts run on the host browser JS VM rather than an additional interpreter.
 
+## Setup GodotJS in Godot Engine
+
+### 1. Clone the source code of godot:
+````shell
+git clone git@github.com:godotengine/godot.git
+````
+
+or
+
+````shell
+git clone https://github.com/godotengine/godot.git
+````
+
+### 2. Checkout the correct version branch
+
+Look at this [list](https://github.com/godotjs/GodotJS/blob/main/.github/workflows/runner.yml#L36) to see supported Godot versions.
+
+### 3. Clone GodotJS module
+
+Clone this module and put it into ``godot/modules/GodotJS``:
+
+````shell
+git clone git@github.com:godotjs/GodotJS.git godot/modules/GodotJS
+````
+
+or
+
+````shell
+git clone https://github.com/godotjs/GodotJS.git godot/modules/GodotJS
+````
+
 ## Supported Platforms
 
 |                | v8               | quickjs         | quickjs-ng      | Web Builtin JS      | JavaScriptCore  |

docs/documentation/building-from-source/v8.md

@@ -123,12 +123,7 @@ use_rtti = true
 ## Setup V8 in GodotJS
 Follow the instructions below to set it up:
 
-**STEP 1:** Download or clone the repo into the `modules` directory of your Godot engine source:
-
-```sh
-cd YourGodotEngineSource/modules
-git clone https://github.com/ialex32x/GodotJS.git
-```
+**STEP 1:** Follow the instructions in [Build from Source](index.md#setup-godotjs-in-godot-engine) to setup `GodotJS` module in the source code of `Godot Engine`.
 
 **STEP 2:** Put `v8` headers and libraries into `GodotJS`, or directly download the prebuilt `v8` from [GodotJS-Dependencies](https://github.com/ialex32x/GodotJS-Dependencies/releases):
 
@@ -164,8 +159,6 @@ The module directroy structure looks like this:
         ┣━ ...
 ```
 
-The currently used version of `v8` is `12.4.254.21`.
-
 **STEP 3:** Compile and launch `Godot Editor`. Then, you can create a Godot project in TypeScript/JavaScript:
 * [Create-a-TypeScript-Project-from-Scratch](Create-a-TypeScript-Project-from-Scratch)
 * [Create-a-JavaScript-Project-from-Scratch](Create-a-JavaScript-Project-from-Scratch)