How does disk cloning works?

Hello Techies,
I need to reformat 15 computers in my friend's internet cafe. What I'm planning is, I would reformat just one computer and install all the games and applications needed.
Then, I would use Acronis to clone or make an image of this computer and use this image on other computers. Is that possible and how will I do that?
Do the other computers need an operating system before I install the clone /image of the computer I've worked on, to other computers?
What do you guys think?
I would need all possible technical advice from all experts here.
Thank you very much.
