For a step-by-step introduction, download the Scratch 1.4 Getting Started Guide. The Scratch 1.4 Reference Guide has a thorough explanation of the Scratch interface and programming language. Scratch Cards provide brief explanations that show how to make animations and interactive projects with Scratch.
Display: 800 x 480 or larger, thousands or millions of colors
(16-bit color or greater)
Operating System: Windows 2000 or later, Mac OS X 10.4 or later,
Ubuntu Linux 9.04 or later (For other versions of Linux, see the
Linux Installer page)
Disk: at least 120 megabytes of free space to install Scratch.
CPU and memory: Most computers have enough memory to run Scratch
1.4, but very old computers may run Scratch slowly.
Sound / Video: Sound playback requires speakers (or headphones),
and recording requires a microphone. Many laptops have speakers
and microphones built in. Scratch 1.4 can use a USB or built-in
camera (optional).