My xiao nrf52840 sense can't find the port of uart with windows

I download bootloader by j-link into xiao nrf52840 sense board,when i connect the usb of xiao nrf52840 to windows usb, it just show a nrf serial device,so how can i fixed to change to comX port of uart?

this is eth bootloader that i download into xiao board:

AFAIK, Windows decides which Com port it assigns to a device. You may be able to change that in the windows device manager. Besides that, the bootloader is responsible for uploading firmware. When pushing reset twice, if should offer a disk service to the PC, and a drive should pop up at the PC, into which you can upload a firmware. This is a ‘virtual’ drive, so it does not show a real file system at the board.