Hi Pierre,
For DesignScript have you already seen these documents?
http://dynamobim.org/developer/index.html
http://dynamobim.org/wp-content/links/DesignScriptGuide.pdf
http://dynamobim.org/wp-content/links/DesignScriptDocumentation.pdf
For Python there are lot of examples here:
http://revitpythonwrapper.readthedocs.io/en/latest/index.html
and here