Adds initial documentation for NPM package installation

docs/gitbook/installation/npm-package.md

@@ -1,3 +1,61 @@
 # Npm package
 
-soon
+## Installation via NPM Registry (recommended)
+
+The easiest way to install Garaga is via your prefered Node.js package manager, such as `npm` or `yarn`.
+
+1. Open your terminal or command prompt.
+2. Run the following command:
+
+    ```bash
+    npm i -S garaga
+    ```
+
+    or
+
+    ```bash
+    yarn add garaga
+    ```
+
+{% hint style="info" %}
+{% endhint %}
+
+## Building the package from source code
+
+The package can be build directly from source code by cloning the garaga repository. Make sure you have both [Rust](https://www.rust-lang.org/tools/install) and [Node.js](https://nodejs.org/en/learn/getting-started/how-to-install-nodejs) installed in you machine.
+
+1. Open your terminal or command prompt.
+2. Install wasm-pack by running:
+    ```bash
+    cargo install wasm-pack
+    ```
+3. Run the following commands:
+
+    ```bash
+    git clone https://github.com/keep-starknet-strange/garaga.git
+    cd tools/npm/garaga_ts
+    npm ci
+    npm run build
+    npm pack
+    ```
+4. The .tgz file with the package contents will be available in the current folder.
+5. Install the .tgz file in your project
+    ```bash
+    npm i -S <path-to-tgz-package-file>
+    ```
+
+For reproducible builds, one can use instead docker compose. Make sure [docker](https://docs.docker.com/engine/install/) is installed in you machine.
+
+1. Open your terminal or command prompt.
+2.  Run the following commands:
+
+    ```bash
+    git clone https://github.com/keep-starknet-strange/garaga.git
+    cd tools/npm/garaga_ts
+    docker compose up --build
+    ```
+3. The .tgz file with the package contents will be available in the current folder.
+4. Install the .tgz file in your project
+    ```bash
+    npm i -S <path-to-tgz-package-file>
+    ```