2. How to set the brightness level and display mode of the pulsing light?
You can set them in Settings -> Display -> Indicator light control.
And there're 3 control options:
Brightness: set the brightness to a fixed level or make it change according to the current volume level (check the option 'Follow the volume' );
Charging: set the light to be constantly on, pulsing or OFF during charging;
Working: set the light to be constantly on, pulsing or OFF when the player is in normal working status