Why does the computer not see the keyboard and mouse?

Question

Iron

I assembled the computer, connected everything, but for some reason the keyboard, mouse (usb, connected directly to the motherboard) do not work, and there is no image on the monitor. What to do?
Mat. board - Asus Prime H310M-R R2.0
Processor - Intel Core i3-9100f
Power supply - Be Quiet 500 W
There is a video card, I connected the monitor there.
The cooler rotates, i.e. the motherboard is working. What to do?
Sorry if I'm asking the question in the wrong place.

Answer 1

Video card, memory modules fully inserted, clicked? Did you connect power to the video card and processor with separate lines? Try a different output on the video card. Disconnect all wires except power on from the motherboard for a while (usb, front panel, etc.).

Answer 2

Did you forget to insert RAM?)

Answer 3

IMHO, there is a chance that the bios needs to be updated to support the processor.
https://www.asus.com/Motherboards/PRIME-H310M-A-R2...

Answer 4

Either there is contact where it is not needed, or there is no contact where it is needed.

Answer 5

plug in the buzzer - it should be included
depending on the number, in the manual you can see what exactly it falls on, it
can be anything, maybe something is not so connected, maybe my mother is not in order
somehow it didn’t load for me due to the fact that one of the new RAM sticks was defective

Answer 6

The cooler rotates, i.e. the motherboard is working.

Wrong conclusion. The cooler is spinning because it has received power. The coolers are powered by the 12V line, which is not connected to the mother in any way.
Pick up a beeper (sometimes it comes with the mother), a speaker (if it's lying around) and listen to how it squeaks at startup.