All modern operating systems have some common features--at least with the graphical interface. Beneath the surface, they are very different---any Linux system is--at the core--very different from Windows. But--to the user--many of them WORK in similar ways.
One of the really great things is that most popular versions now come in a "Live CD" form. You don' have to install anything---just boot the CD and dive in. (Keep in mind that Live CD is slow---don't conclude that this is a Linux feature until you actually install.)
Try the "getting started" link below.