Twrp can’t mount storage to flash rom or dfe

im sorry im a bit noob in flashing rom ..
i unlocked bootloader, flash twrp using adb fastboot with command line ..
the issue start here, twrp cant read any storage, connected usb my pc to phone, not storage detected,
can’t copy rom to flash,
tried formatted data using twrp, can see storage size in twrp, but still pc cant detect storage and cant copy rom file
after booted, storage got decrypted again..
can anyone help? im otw to flash miui eu