Sitting with your legs bent and arms stretched forwards, first push off and stretch your legs, then pull your arms towards your head with your upper body leaning slightly backwards. Return to the starting position in exactly the opposite way: first stretch your arms, then move your upper body forwards and finally pull your legs forwards. In theory, the rowing movement sequence sounds complicated, but many of the individual movement sequences are already performed correctly unconsciously:

Starting position:

Upper body bent forwards towards the thighs.
Back muscles relaxed.
Lower back straight, upper back (trapezius muscle) may make a slight hump.
Arms stretched (triceps remain relaxed).
Tummy muscles slightly tensed.

Starting the pull-through:

Legs lead the movement by stretching them.
At the same time as stretching your legs, slightly tense your lower back and bring it into a straight position.
The phase ends when your legs are almost fully extended.

Middle phase of the pull-through:

From this phase, the upper body also comes into play.
The arms and back now dictate the movement, with both parts of the body being pulled backwards almost simultaneously (between the chest and belly button). The strength comes from the back and not the arms.
The abdominal muscles and thigh muscles remain tensed the whole time.
The phase ends with the upper body leaning slightly backwards and the arms slightly raised. The back shoulder is already working slightly.

Final move:

Pull your arms completely towards your body.
The upper body leans back a little further in the same move. The back shoulder is now even more involved.
Tighten all the muscles involved (buttocks, thighs, abdomen, arms and shoulders).

Rolling:

Arms lead the way.
Stretch your arms forwards again. The upper body and legs follow the arms.
The buttocks pull the seat forwards.
The phase ends in the starting position.