If you're interested in cutting your cholesterol, but don't know how to start, a new booklet called "Cholesterol Countdown" can help.

Written by Dr. Irene Rosenberg and Annette Natow, a registered dietitian, the 38-page publication explains in plain, everyday language how to lower cholesterol levels through diet.The booklet explains the differences between "good" and "bad" cholesterol and discusses the link between dietary fat and serum cholesterol levels.

It includes charts of different foods' cholesterol levels and quizzes to help evaluate your diet.

The authors suggest eight steps to reduce your cholesterol. They are:

- Eat less fat.

- Use monosaturated fats and oils.

- Eat more high-fiber food.

- Don't drink more than 2 cups of coffee a day.

- Don't drink more than 2 alcoholic drinks a day.

- Eat fish 2 or 3 times a week.

- Increase physical activity.

- Keep your weight within recommended limits.

For a copy of "Cholesterol Countdown," send your address and a check or money order for $4.95 to Wellness, P.O. Box 370, Woodmere, N.Y. 11598.