Grub Rescue Unknown File System

Hello. I want to install Windows 10 with dual boot.
So I reinstalled Manjaro, by manual partitioning I installed on 750GB, and made 200GB free partition for installing Windows later.
I made myself Windows USB, I press F12 then select the Windows USB to boot from it.
It says:
grub rescue unknown file system
As you see grub does not recognize my installer USB. How can I fix that and boot from that USB?

Is that Windows USB an installation media? Shouldn’t you boot it from the motherboard’s boot selector, rather than Grub?