This is a three-exercise combination move. You'll simply perform 8 to 12 repetitions of each exercise, one after the other without resting. So do 8 to 12 reps of the Floor Y raise, followed immediately by 8 to 12 reps of the Floor T raise, followed immediately by 8 to 12 reps of the Floor I raise.
Floor Y Raise
Lie facedown on the floor with your arms resting on the floor, completely straight and at a 30-degree angle to your body, so they form a "Y." Your palms should be facing each other, so that the thumb side of your hand points up [A].