Pleasebiosnodisplay

I was building my friends pc when i was going to install Windows and my monitor didnt detect any signal from gpu tried a tv too i also had a problem in Which my keyboard and mouse would not work the keyboard led would turn off after 1 sec and tried of both motherboard usb and case usb please checked all cables and pins too make sure they were fully flush and correcty inserted pkease help

Hi i was building my friends pc when i finshed and was about to install windows and the bios woundt appear my mother board was a msi z370 a pro anf my cpu 8100 lga1151 i also haf a issue in which niether the motherboard usb or case usb would read my keyboard please help