https://www.raspberrypi.com/software/
1. Change KC868-Server USB boot jumper
2. Connect with USB cable with computer and KC868-Server
3. Power on of KC868-Server
4. Run rpiboot
5. Download and install Raspberry Pi Imager
6. Manually install an operating system image
7. Connect KC868-Server HDMI to monitor
8. Connect keyboard and mouse to KC868-Server