These are some videos that show some basic tasks in Matrex.
For more information, give a look to the documentation.

Connect to a Matrex Server
Connect to server
Matrex connecting to a server, copying a project to it and opening it.
Random videoBuilding of a project containing only a random function that produces a random matrix.
Expression ParserExpression Parser VideoWriting a formula in a project.
Chart Chart VideoAdding a chart showing a normal distribution to a project.
 PresentationPresentation VideoAdding a presentation to a project.
Xls ImportXls Import VideoImporting an xls (Excel) file in a project.

The videos have been recorded using pyvnc2swf.