The 5.3.3 release is a minor release to fix among others two serious bugs:
This help is also available on http://help.scilab.org. It provides some advanced features like comments, favorites, search engine, etc.
If you are new to Scilab, you can have a look to the Scilab's keyword help pages.
The Scilab Consortium provides some documentations and tutorials.
Many other documentations are also available through the Scilab website.
Scilab Home page - Consult Scilab official website
Wiki - Consult documentations, tricks, etc
Bug tracker - Report bugs and wishes about Scilab
Forge - Browse and publish Scilab modules
Mailing list archives - Communicate and exchange with the community
ATOMS - Browse Scilab packaged modules
File exchange - Exchange your scripts, results and files.