Add more details about the different course edition flows.

30.about/10.contributing/page.en.md

@@ -5,12 +5,13 @@ slug: contributing
 
 ## Philosophy
 
-Each course is subject to the licence its original authors chose.
-Translations should probably follow the same licence as the original works.
+Each course is subject to the license its original authors chose.
+Translations should probably follow the same license as the original works.
 
 ! @cmeny Drop a line here about the structure with 4 levels.
 
 
+
 ## How it works
 
 
@@ -30,6 +31,8 @@ Translations should probably follow the same licence as the original works.
 
 ## Data Flow
 
+Here's a breakdown of three different ways of contributing to the courses.
+
 ```mermaid
 
 graph RL
@@ -54,6 +57,24 @@ GitLab --> |updates| Website
 <marquee>🐠</marquee>
 
 
+#### Via GitLab
+
+You only need a modern browser to [use the WebIDE](https://m3p2.ljbac.com/-/ide/project/m3p2/courses/edit/master/-/).
+
+!!! GitLab's preview may differ slightly from the end result.
+
+
+#### Via Git
+
+Setting up a Git client can be intimidating, but it allows offline edition of the courses.
+You can use your favorite text editor.
+
+#### Via Local Website
+
+This third level of edition is for experts who can [run the website locally](https://m3p2.ljbac.com/m3p2/grav-website#run-locally-for-fast-development)
+to instantly preview their changes, and use Grav's admin tools for page edition.
+
+
 ## Enhanced Markdown
 
 The point of Markdown (compared to raw HTML) is the _readability of the source_.