where can I download the correct file? How can I put that in one USB or SD card? I need to try it without install it on my HD.
Regards in advance.
The file you get from http://www.ubuntu.com/download/desktop provides both installing and testing. Download Ubuntu 14.04. Then look over here to learn how to create a live usb stick. Also, make sure to enable booting from usb in your bios settings in case it isn't set that way anyway.
dd
command (Mac hasdd
command, right?)