Setup and Key Actions
From hands and knees, bring your big toes to touch, sit back on your heels, lengthen through your spine, and rest your forehead on the floor. You can extend your arms forward or rest them alongside you. Relax your face and your jaw. Notice the places in your body that move as you breathe.
Modifications
If having your thighs together in this pose feels uncomfortable, keep your big toes together but separate your knees as wide apart as you like. If child's pose bothers your knees, you can place a rolled up blanket behind them or practice with your hips a foot or so higher in the air (puppy pose), which can also be a nice variation if traditional child's pose bothers your lower back.