Connect a MIDI cable to the "MIDI Out" jack on the rear panel of your keyboard. Connect the other end of the MIDI cable to the "MIDI In" jack on the QY70. This creates a communication channel between the MIDI controller and the sequencer.
Turn on the QY70. The device will automatically recognize the externally connected MIDI keyboard.
Press the "Menu" button on the top-right of the QY70 control interface. Use the triangular, arrow-shaped buttons to scroll through the menu. Press enter to select your preferred sound from the menu. The MIDI keyboard will trigger that sound remotely. The benefit here is that you can access a wider range of pitches using your keyboard. The QY70 has a wide range of pitches too, but you can't access them at the same time, you first have to press the "Oct Up" or "Oct Down" keys to transfer the 25 micro keys into a new octave. This is restrictive if you are trying to compose a melody.
Press the "Song" button to open the song sequencer function. A sequencer is an interface from which you arrange portions of music, for example transporting drum loops from one bar to another.
Press the red "Record" button on the extreme-left of the navigation section. Anything you play on the keyboard is recorded to the internal memory of the QY70. As soon as you start recording, the LED display brings up a new menu, including a "Save" option.
Select "Save" by pressing the corresponding button to the right of the LED menu.
Press "Menu" to access a range of editing options. Although you selected a specific sound before recording, because this is MIDI and not audio, the QY70 recorded data and not sound. This means that you can change the sound of the recording by selecting a new sound from the menu.