This document is a user manual for the AP220CH1B digital piano. It provides detailed information on the functions and usage of various parts of the digital piano, including the function buttons, power socket, headphone and audio device connections, tone selection and playing, sound effects and metronome usage, recording and playback functions, keyboard configuration and tuning. It also explains how to connect the digital piano to a computer and transfer MIDI data. The digital piano offers a variety of tones and features, making it suitable for various music performances and practice sessions.