docs: improve overview section

CONTRIBUTING.md

@@ -18,7 +18,7 @@ Include the relevant issue number if applicable.
 
 ## Do you intend to add a new feature or change an existing one
 
-* Suggest your change by [opening a 'Feature request' issue][5] and start writing code.
+* Suggest your change by [opening a 'Feature request' issue][5] and start writing code (following the [developers guide](DEVELOPERS.md))
 
 ## Do you have questions about the source code
 

DEVELOPERS.md

@@ -1,11 +1,15 @@
 # Developers guide
 
+## Prepare
+
 Install the dependencies
 
 ```bash
 npm install
 ```
 
+## Develop
+
 Build the typescript and package it for distribution
 
 ```bash
@@ -24,3 +28,11 @@ $ npm test
 
 ...
 ```
+
+## Contribute
+
+Before creating a commit, validate your changes and build the associated distribution files
+
+```bash
+npm run all
+```