Scratch 1.4's Screen Layout:

Scripts :  are the puzzle pieces that make up your program.  The scripts are organized into categories that can be selected at the top left.

Programming Area:  this is where you drag your scripts to use.

Sprites:  these are the characters in your game.  The program always starts with the basic Scratch Cat sprite.  They can also be elements in your game that you want to program (walls, doors, the ground, etc).

Stage:  the stage is the background of the game.  It is blank to begin with but you can move scripts into it to program it.

Making Programs:

To create a program, all you have to do is drag and drop pieces on the left side to the middle programming area:

Starting A Program

Programs can only be started with scripts that have bumps on top of them.  There are only 4 scripts with this, and they are located under the Control category and labelled below:

Getting Help

To get help on any script in Scratch, all you have to do is right click on the script and press help.  It will give you an explanation and/or an example of what the script does.