If I'm right, Mint Linux is based on Ubuntu so provided that you have the needed hardware (namely a graphics card that is capable of working some 3d and has drivers for Linux - usually nVidia or ATI card) it should be easy:
- if you haven't yet, install drivers for your graphics card that provide you with hardware accelaration
- install compiz-fusion packages using your package manager (including the configuration utility)
- run compiz-fusion and configure the cube plugin (and others if you like)
Compiz-fusion web site probably has docs about how you use and configure it, so check the site out for that. For installing the graphics card driver (not needed if you are already using it) and compiz-fusion packages use your package manager - Synaptic if Mint uses it, or something equal (or apt-get or aptitude from command line).
You'll see if your graphics card has Linux drivers by reading the manufacturer's website; ATI's and nVidia's sites at least have lists of cards that work with their Linux drivers. The drivers are available at the web sites, but it's a lot easier to use your package manager (Synaptic for example) to install the driver package to your system, that way it's more automatic and cleaner to install and easier to upgrade later on. To see if you have hardware accelaration capabilities, run
and look for direct rendering (is it on or not) in the beginning.