Posture and hands
Sitting at the piano
Sit on the front half of the bench, back straight but relaxed. Elbows level with the keys or slightly above - adjust the seat height if needed. Feet flat on the floor.
Your distance is right when your outstretched fists reach the fallboard: the elbows get room to move.
Hand shape
Imagine holding an apple: fingers rounded, wrist loose and level with the forearm. Press the key with the fingertip pad, not a flat finger.
Fingers are numbered from thumb to pinky: 1 - thumb, 2 - index, 3 - middle, 4 - ring, 5 - pinky. These numbers - the fingering - are printed under the notes.
Check yourself
1. Which finger is number 1?
2. What part of the finger presses the key?