The detailed tutorial for whistling by hand is as follows:

1. First wash the whistling hands with clean water, then wipe off the moisture on your fingers and keep them dry.

2. Put the fingers of both hands together to form an inverted V shape and extend them to your mouth.

3. Clamp the underside of the tongue tip with two fingers, and push the two small holes under the tongue tip outward.

4. Leave a small hole open to allow air to flow out smoothly.

5. Use your middle finger and index finger to hold your lower lip and press your lips downward.

6. Use your ring finger and little finger to hold your upper lip and press your lips downward.

7. Use your middle finger and index finger to open your mouth slightly and let the air blow out of the whistle.

8. Practice repeatedly until you can whistle proficiently.

How to whistle:

1. Practice making sounds. At first, you can try making a "hissing" sound with a short burst of air, or imitate the sound of a kettle boiling. Through this exercise, you can exercise the muscles of your lips and improve their flexibility, making it easier to whistle.

2. Learn the correct whistle posture. Put your lips together, raise the corners of your mouth slightly, and let the air flow out from the middle of your lips through the cooperation of your mouth and tongue. Be careful not to use too much force to avoid excessive tension on your lips.

3. Gradually increase the difficulty of playing. Try playing simple notes and songs, starting with simple melodies and working your way up to more difficult ones. You can refer to some whistle tutorials or practice along with the music.

4. The practice time is gradually extended. Don't expect to be able to whistle for a long time at the beginning. You can gradually increase the practice time, starting with a short period of time and slowly extending it until you can whistle comfortably.

5. Try using different finger combinations. When whistling, try using different finger combinations to get different tones and sound effects.

6. Find a whistle mouth shape that suits you. Different people have different mouth shapes and lip shapes, so you need to try different whistle mouth shapes to find the mouth shape that suits you.

7. Pay attention to the rhythm and rhythm of the whistle. When whistling, you need to pay attention to rhythm and rhythm. You can improve your whistling skills by imitating songs or creating your own rhythm and rhythm.