trouble installing windows 10 via bootcamp

Hi, I have been trying to install windows ten on my macbook air (2020 with an intel processor) via bootcamp, i downloaded a windows ten disk image and installed the bootcamp software fine, but when I used a usb flash drive (I did download windows onto it using the steps on the apple website) Windows is not showing up as an option when i restart my mac. Only an image with macbook comes up as an option, not bootcamp or windows, any advice on how to fix this would be appreciated!