Adjust the carriage so that the handle bar is slightly higher than your belly button.
Stand legs hip-width apart, back against the bar. Take the bar, keep shoulders low and elbows back. Upper body and stomach are tense.
Press the handle-bar down evenly until the arms are stretched. Then return slowly to the starting position.
Stand as close to the handlebar as possible. Keep your core stabile and shoulders down. Do not tilt back.
The closer you keep your elbows to the body and to the back, the more you train the triceps.