doc: add local setup guide

.github/readme/partials/documentation/setup/local.md

@@ -2,3 +2,37 @@
 
 *Documentation not available yet*
 
+## 0️ Prepare your machine
+
+A machine with a recent version of [NodeJS](https://nodejs.org) is required (see used version in [Dockerfile](/Dockerfile#L1-L2)).
+
+## 1️ Clone repository and install dependencies
+
+Run the following command to clone this repository and install dependencies.
+
+```shell
+git clone https://github.com/lowlighter/metrics.git
+cd metrics/
+npm install
+cp settings.example.json settings.json
+```
+
+## 2️ Setup and configure *metrics*
+
+Follow [🏗️ Deploying a web instance (~20 min)](/.github/readme/partials/documentation/setup/web.md) guide except docker-related sections.
+
+Once read, start local instance using the following command:
+```shell
+npm start
+```
+
+## 3️ Start hacking!
+
+Connect to your web server using `http://localhost:{port}` and start hacking!
+
+For quick testing, it is advised to directly craft URLs, rather than using the web interface.
+
+*Example: test a new plugin*
+```shell
+https://localhost:{port}/username?base=0&newplugin=1&newplugin.option1=hello&newplugin.option2=world)
+```