Question Pc fans and power button not working while motherboard light when ever the psu is turned on

[Nas_07]

I've tried to run the fans to make sure the case works but as you see nothing worked beside of the motherboards LED. I needed an adapter to plug the RGB controller to the motherboard and as I know you can run the pc without plugging it there because it is only for controls l've also tried to plug the back fan in the CHA_FAN2 but nothing worked I don't know what I have done wrong but y'all I need help this is my first ever build n I am ab to freak out my case is NZXT h7 elite and the motherboard is rig strix b550-f gaming Il with the NZXT c850 l've been string here for the past 5h trying to figure out what's happening by the way only the psu is bought used and it look in great condition so Idk I need help rn

You can see it in video in here :
https://share.icloud.com/photos/068BiHHcUtY_L3FF1KAi8lBoA

 

[rgd1101]

full system spec? include brand and model of the psu

 

[Nas_07]

full system spec? include brand and model of the psu

I was just trying to run the fans and case without nothing beside of the case ,psu , and mb
Case : NZXT H7 elite
Motherboard: rog b550-f gaming II
PSU: NZXT c850 gold

I got all of the other parts if it is only going to work with it additionally the motherboard is from Emirates idk why but it was brand new

 

[NOR1NCO]

You're seeing the motherboard's 5V STBY power. Remember, the system fan needs 12V to run. Without a CPU, the motherboard's protection circuit might block 12V power

 

[Nas_07]

You're seeing the motherboard's 5V STBY power. Remember, the system fan needs 12V to run. Without a CPU, the motherboard's protection circuit might block 12V power

My rgb controller is 5v I’ve also tried connecting it to the mb 12v rgb header it didn’t even stay on couldn’t plug it additional I’ve assembled all of the parts beside of the gpu because my cpu is graphic integrated, nothing have worked my cpu cooler is also 5v I’ve connected the cable at the cpu fan and the other at the other rgb header that is 5v, additionally my rams are rgb I did connect them but they didn’t light . I’ve use a pin jumper to test the power supply and the fan started but I bought this motherboard from facebook marketplace for 125 and it retail for 185 it was brand new never been opened but there was a QR code which says TDRA and it was from Emirates

 

[NOR1NCO]

Memory and CPU are powered by the 12V main power supply through voltage reduction chips. Even if the hardware is incompatible, when you press the power button, the motherboard's chipset will attempt to execute the boot process through the firmware, and there should not be a situation where there is no power or the components do not light up. I would recommend carefully examining both the front and back of the motherboard to check for any visible damage or component failure.