Feet can be hip distance (gives more balance) or together. From standing breath out as you fold forward this should come from the hips not the back. How far down you get will depend on the length of your hamstrings and to some degree flexibility in your hips. If you are not flexible in the hamstrings keep the legs straight and go down keeping the back flat and the neck long look towards the floor. Place your hands just above the knees. If you can go further down put you hands/fingers on the floor and they need to be heading level or behind the toes. Your gaze point will change depending on how far down you get but concentrate on keeping the neck long and relaxed. No matter how far you go down keep the legs straight, your weight towards the toes and tilt the pelvis upwards. To engage the quads (front of leg) lift the knee caps. This is a great pose to hold and as you breath feel the release in the hips and backs of the legs. Deep breath and send your thoughts and energy to the areas which feel restricted.