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