Creating a window in libSDL
A window in an application is the most basic part of the drawing process. LibSDL offers a way to create one regardless of the graphical environment or operating system being used. Each window uses the surface object, which contains basic information about the drawing context, such as the inner window size, color depth, pixel format settings and optional flag variables to set up the drawing process. LuaSDL allows you to set up these window parameters in a simple manner.
Moreover, libSDL operates with the screen as the surface object representation. LibSDL 1.2 allows you to use only one window, while the current version of libSDL 2.0 allows multiple windows. This might be the deciding factor when deciding whether to use the older version of LuaSDL or the newer LuaSDL 2.
Getting ready
LibSDL 1.2 offers an old interface to set up a window but it's sufficient for simple games and multimedia applications. Most likely you'll want to use the whole screen for your application...