ARM Android-nn-driver Build Issue

[janani-sundaragandhi]

I'm trying to build the android-nn-driver by cloning it and pushing to ANDROID_ROOT following the integration guide. Currently the steps to generate the driver from the below step is unclear.
Update the Android build environment to add the Arm NN driver. This ensures that the driver service is built and copied to the system/vendor/bin/hw directory in the Android image. To update the build environment, add to the contents of the variable PRODUCT_PACKAGES within the device-specific makefile that is located in the <ANDROID_ROOT>/device// directory. This file is normally called device.mk
I'm seeing the device.mk files & its dependent mk files in build of cloned repo (git clone https://android.googlesource.com/platform/manifest). Not clear about the linkage between the ADB shell and the android google source cloned repo.
device/ directory is in android google source clone & vendor/ directory is in adb shell ANDROID_ROOT. Please explain the linkage between these two.

Can someone explain/provide the clear steps to build the android-nn-driver using the android emulator & ADB shell.