Start at your feet, take a deep breath, arch your feet, hold your breath while you keep the muscles tensed.  Slowly breathe out as you release the tension in your feet. Repeat this.

Move to your calves and tense those muscles - breathing as you tense, holding your breath and slowly breathing out as you release those muscles. Repeat.

Repeat this with your thighs, abdominal muscles, stomach and back, chest and upper back.  

Tense and release hands, arms and shoulders at the same time.

Continue to move up your body tensing and releasing neck, then jaw and temple and scalp muscles.

If you have difficulty tensing certain muscles, just focus on them as you inhale, hold and exhale.

If tension remains - start at head and tense and release muscles until you are back to your feet.