docs: improve CONTRIBUTORS guide(s) (#153)

Author: fraxken

CONTRIBUTING.md

@@ -18,6 +18,16 @@ that *all* contributors are expected to follow. This code describes the
 
 See [details on our policy on Code of Conduct](https://github.com/NodeSecure/Governance/blob/main/COC_POLICY.md).
 
+## First-contributor guide
+
+If this is your first open source contribution, we [have a special guide](https://github.com/NodeSecure/Governance/blob/main/guides/contributor-en.md) to help you.
+
+## Discord
+
+Our project has a discord that allows mutual cooperation between (new-)contributors. We are very welcoming and respectful, do not hesitate to come and ask us questions if you are in trouble.
+
+[![OpenAlly](https://discordapp.com/api/guilds/640183220452720650/embed.png?style=banner2)](https://discord.gg/4Wn8rjAtB4)
+
 <a id="developers-certificate-of-origin"></a>
 ## Developer's Certificate of Origin 1.1
 

README.md

@@ -62,8 +62,13 @@ or
 ```bash
 $ git clone https://github.com/NodeSecure/cli.git
 $ cd cli
+
+# install NPM dependencies using package-lock.json
 $ npm ci
+
+# run esbuild to bundle/compile front-end assets
 $ npm run build
+
 $ npm link
 ```
 
@@ -183,6 +188,26 @@ See [Scorecard Public Data](https://github.com/ossf/scorecard#public-data):
 > We run a weekly Scorecard scan of the 1 million most critical open source projects judged by their direct dependencies and publish the results in a BigQuery public dataset.
 > Currently, this list is derived from projects hosted on GitHub ONLY.
 
+## Contributors guide
+
+If you are a developer **wishing to contribute** to the project, you must first read the [CONTRIBUTING](./CONTRIBUTING.md) guide.
+
+If you have already cloned and installed the project with npm locally, you still need to build and bundle front-end assets using the npm `build` script:
+
+```bash
+$ npm run build
+```
+
+> **Warning** restart this command when modifying files in the public root folder
+
+Once you have finished your development, check that the tests (and linter) are still good by running the following script:
+
+```bash
+$ npm test
+```
+
+> **Note** If you add a feature, try adding tests for it along.
+
 ## Contributors ✨
 
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->