Question about ASUS ROG STRIX B550-F GAMING

Have you supplied your cpu with power?
the 8pin power cable in the upper right corner of the mainboard.

Addendum:
In the meantime, I never get a signal from the graphics card.
The fans of the graphics card turn on start-up.
Tried 2 monitors, both with HDMI and DVI, plus output on the MB, all no sginal.
Then I installed an old spare graphics card: same thing.