. Snow Leopard was the last major version of macOS distributed primarily via physical DVD media. How to Obtain Snow Leopard Official Updates : Apple offers free "Combo Updates" (e.g., v10.6.8) on the Apple Support Downloads page
Before attempting an installation, ensure your hardware is compatible: Mac OS X v10.6 Snow Leopard - Technical Specifications Mac Os X 10-6 Snow Leopard Download Dmg