Prasarita padottanasana is one of my favourite yoga poses!
Try to keep your back as straight as possible making your heart reach forward pulling your navel towards your spine.
Your sitting bones are moving towards the seiling.
Bend your knees slightly if this is to deep of a stretch for you yet.
You can keep our arms straight and directly under your shoulders, maybe even using some blocks or books if you cant reach the floor with a straight back.
My new beginners yoga course at Yogaloftet Fana is now fully booked but feel free to get in touch for a private class or course.