List your chapters on the left side of the page. If you're using graph paper, you may want to leave one or two rows blank between chapters so there's enough room to write.
List your characters at the top of the page, from left to right.
Write a one-sentence summary of your story at the bottom of the page. Ask yourself what happens. Determine what the characters want and what will get in the way of those desires. Write a paragraph containing the desires and obstacles.
Create an extra column for chapter summaries. This can be to the left of the character columns or to the right.
Fill in the summary column for each chapter. Keep it to one or two sentences per chapter.
Figure out which characters are in which chapters. Either put an X in the character's column corresponding to the chapters they're in or get more detailed. Should you choose to get more detailed, list the character's desire and the obstacle to that desire for each chapter.