You need the data files of the original game(s) you wish to play and a distribution of ScummVM for the operating system you are using, which can be found in our [http://www.scummvm.org/downloads.php downloads] page
=== What are the "stable" and "unstable"
(SVN) versions of ScummVM? ===
The stable version of ScummVM has been checked for bugs, and people have completed almost all of the games that ScummVM supports using it.
(Subversion or SVN) version of ScummVM includes improved functionality, however when new features are added or existing bugs are fixed, other bugs or crashes may appear, which were not present in the stable version. However, we do of course still try to make the unstable version as stable as possible.
== Further reading ==
That was a short introduction of ScummVM, we hope that we've answered most of your questions. You may now refer to the pages in this wiki for more information, our [http://www.scummvm.org/faq.php FAQ] and our [http://www.scummvm.org/documentation.php documentation page], especially the [http://scummvm.svn.sourceforge.net/viewvc/scummvm/scummvm/branches/branch-0-10-0/README?view=markup README] file.