Help with computer software problems?!?

Hi, Im new to this 'encryption' computer jargon. So what I want to do is to download a software called 'Tails'. But first I need to verify the IOS image. I did download it. However, when I opened the file up, a window with 4 folders appeared. the names are as follows:
EFI, isolinux, live, and utils.
I DO NOT KNOW WHAT TO DO. on their website (TAILS' website), it says that in order to verify, I need to download a software called Gnome. then the instructions go on to say "
Using Linux with Gnome: Ubuntu, Debian, Tails, Fedora, etc.

?2014-10-09T07:30:53Z

First thing, are you running some version of linux?
Gnome is a user interface for various distributions of linux, including Fedora.
If you are using Fedora, you can use yum to download and install tails
If you are using Ubuntu or some other debian distro, you can use apt-get to download and install it

If you are running Windows, then you are downloading the wrong version.