Here you can find screencasts about installation and using Matlab.
To install Matlab, you first need to have the activation key. You will find this at http://www.ekstranet.its.aau.dk/software/mathworks/download-mathworks/ (you will need to log in). When you have logged in, press the "Students" link. Save the document.
Afterwards you need a MathWorks account that must have the activation key attached. You do this by following the steps below. There is also support available at http://www.ekstranet.its.aau.dk/software/mathworks/mathworks-support/ that you can use if you get problems during the steps below.
Then Matlab can be installed as described here: http://www.ekstranet.its.aau.dk/software/mathworks/mathworks-support/.
Note that you only need to install "Matlab" and "Symbolic Math Toolbox".