you can find some things here:
https://github.com/offensive-securit...nter-installer
https://github.com/offensive-security/nethunter-app/
https://github.com/jcadduono/nethunter-installer-tools
run ./build.py for whatever device to create a zip that you can pick apart and understand I suppose, boot-patcher/patch.d folder contains scripts to tell you what NetHunter is doing to your ramdisk.
nethunter-installer-tools repo has instructions on how to compile the binaries you see in kali-nethunter repository.
everything is open, let me know if there's anything specific you get really stuck on. I will be in the #nethunter channel on freenode IRC if you need faster communication.
Member of the Kali NetHunter developer team. You can contribute to Kali NetHunter too!
We accept pull requests!
Find my GitHub account: jcadduono