If your recovery has been replaced by the stock recovery, flash it again using
fastboot flash recovery <recovery.img> reboot recovery
If it asks you to run it once again, do so
adb shell msc
diskpart
Use
list volume
to find it, it's the one named WINVAYU
select volume <number>
assign letter x
exit
Unpack the Drivers archive you've downloaded earlier and run the OfflineUpdater.cmd
script
When it asks you for the drive letter, enter X
You can also use the WOA Helper app, in which case you can reboot with
adb reboot
Make sure you use the latest UEFI, because Windows might not boot if you update drivers without updating the UEFI
adb reboot bootloader
Replace <uefi.img> with the actual path of the UEFI image
fastboot flash boot <uefi.img>