Question about ASUS Prime Z390-P

Good day, After assembling the PC, I can't get a picture. The PC is running, the LEDs on the mainboard light up orange/yellow. I have an intel core i7 9700 with only onboard graphics, i.e. without a separate graphics card. My monitor is connected to the HDMI output of the mainboard. Is it possible that I have to connect via the display port to start the BIOS because this is set as the default? Or should it also work via HDMI and I have made the mistake somewhere else? I would be very grateful for a short answer, of course, and I send my best regards. Fabian