Adjust the seat height so that the middle of your chest is aligned with the handles. Grip the handles at just wider than shoulder width.
Push outwards, extending your arms out to a point just before your elbows lock out, then in a controlled motion bend your elbows to retract back to the starting position. Your elbows should remain flared out at roughly 45 degrees. Keep your wrists in line with your forearms throughout the movement. Repeat for the desired amount of repetitions.
Avoid having your elbows flare out at 90 degrees.
Fitness for all, for life.