Stretch the upper thigh with a forward lunge. Keeping the back foot rooted to the ground, take a giant step forward with 1 foot until the knee is bent at almost a 90 degree angle. Keep the knee directly over the front foot. The knee of the back leg should be straight.
Keep your feet in place from the forward lunge, and shift your weight back to stretch the hamstring of the front leg. Bend the back knee, but keep the front knee straight. Lean forward, bringing the body to the front leg. Keep your back straight.
Move into the splits gently. Beginners should not go down all the way to the floor yet. Keep toes pointed and knees straight. Lean forward bringing the body to the front leg and reach for your toes. Keep your back straight. This stretches hamstrings even further, along with the groin and hips.
Repeat all of the above stretches on the other side after standing up.
Move into the center splits from the side splits the second time. Once again this may not be possible for beginners. Keep the toes pointed and bring body slowly to the ground while each leg is spread to the side. Reach forward as far as possible, and keep your back straight.