If you want to install and to test Cloudy, we suggest you to take a look at the Get started. There you will find a lot of information from a basic installation to a installation the system in a virtual machine.
However if your computer’s architecture is based on 64 bit or you have the UEFI system, you must follow some different steps. These steps are explained in this FAQ below, answering the question “I’d like to use a 64 bit architecture version of Cloudy. How can I get it?”.