1, the head and neck is best to keep upright, and the body to maintain a parallel state. 2, the head, neck and body should be as far as possible towards the front, which is called sitting upright, never sit in a distorted position. 3, the body should be perpendicular to the ground, you can lean on the back of the chair, but do not bend over. 4.The shoulders and upper arms try to keep parallel with the body, stay perpendicular to the ground, and keep a relaxed state. 5.The upper arm and elbow should be as close to the body as possible, not always reaching outward. 6.The forearm, wrist and hand should be kept as parallel as possible, and the upper arm at an angle of about 90 degrees. 7, the wrist and hand should be straight, not bent, not tilted in the direction of the little finger. 8.Thighs should be parallel to the ground, calves are perpendicular to the ground, and thighs can be slightly above the knees. 9.Feet should be flat on the ground, or can be placed on the footrest.