Basics
Scratch projects are created on line, you will need to create an online account.
After you have created your Scratch account, click on Create and complete the Getting Started with Scratch tutorial located on the right hand side of the editor window.
Scratch Tutorials
There are a number of Introductory Tutorials that introduce a simple programming concepts
These simple programming concepts are also covered these video tutorials
Other Resources:
Getting Started with Scratch is a pdf file to get you started.