In the mini world, to keep playing an instrument, you can take the following steps:

Hold the instrument in your hand and click to enter free playing.

Just click on the keyboard to play.

If you want to play the music you like, you can search for the simplified musical notation and then play accordingly.

After playing it a few times, you will be able to play it once you are familiar with it.

Please note that the above information is for reference only, and the specific operations may vary depending on the game version. If you encounter problems, it is recommended to check the game's official website or consult the game's customer service.