Open the program the screen will look like this.
Like most programs to begin go to file and click new. You can also edit a pre-made project by going to the website http://scratch.mit.edu/, finding a project you like and opening it on scratch. To start, at the far left corner click control these are all conditions, you must have one to begin an action for your character to move, attack, or do just about anything. To create a new character you can ether paint your own or open a picture from a file. To do ether one click one of the icons in the middle left corner. To make a character do something that involves it moving individual body parts or a change of the picture you must draw the animations your self, or download animated gifs from the Internet and import them as costumes by clicking costumes and then import. To paint animations yourself to the same thing except instead of clicking import click paint. To add sounds or music simply click sounds then import or record. For a way more detailed instructions watch tutorials on there website or click help on the program. I don't do scratch anymore because a couple of years ago my parents got me a better program for my birthday, but you can see some of my old projects along with one or two of my brother's here http://scratch.mit.edu/users/skinybones. Tell me what you think.