Previous Position

Double Punch (Heiko Tate Zuki) in Front Stance (Zenkutsu Dachi)

Turn your head to look towards the 10.30 clock position
Breathe in through your nose
Move your Left foot in towards your Right foot
Bring both fists to your Right hip

Step forward towards 9 o'clock with your Left foot so that you finish in a wide front stance, facing the 10.30 clock position

As you step forward, push forward with both fists towards 10.30 to chest height.  Extend your arms fully
Do not twist the fists all the way around.  Your knuckles will face to either side and the thumbs of both fists will be on top, closest to the ceiling
Breathe out slowly and strongly through your mouth during the technique, which should last 2 - 3 seconds. 
Tense all your body muscles for a brief moment on the completion of the move