Start by adjusting the pad to be positioned against your shoulder blades when seated and leaning forward at approximately 45 degrees. Place your feet against the rest and put your hands against your chest.
Start by extending backwards until you go just past 45 degree or what's most comfortable before that, then slowly return to the start position. Activate your core to maintain a straight spine throughout the movement. Repeat for the desired repetitions.
Avoid arching your back or rushing repetitions.
Fitness for all, for life.