It’s the same alignment in both postures.

In Padangustasana, grub the big toes with index fingers and middle fingers.

In Padahastasana, put the hands under the feet.

Try to keep the longest spine also the longest neck. Open the chest and lift the chest. Open the shoulders and relax the neck, so you can breathe longer and deeper.

It doesn’t matter even if you bend knees, as you keep the the chest on the thighs and keep the spine longer.

If you can keep the chest on the thighs and can keep the spine longer, you can strarighten the legs.

As in the basics of any forward bending postures, try not to round the back.

Padahastasana