Enable CCD on DELL 7410 Drallion

I just bought a chromebook DELL 7410 Drallion.
There are no physical buttons on the two sides of this machine. The power button is on the upper right side of the keyboard.
When enabling CCD, it told me to press the PP button.
I pressed the power button once and nothing happened. I pressed it twice and it shut down. I tried many times. I guess the power button is not the PP button.
Does anyone know what I should do?
Thank you.

Is the battery plugged in when you do this? I’ve noticed that if the battery is unplugged, sometimes it will shut down when attempting to open ccd)

It will ask you multiple times to assert physical presence, each time it asks I normally have to press the power button multiple times.