NetHunter2 install on Nexus 10 problems

What I have:
Nexus 10 running 5.1.1
I followed the online instructions.
I installed the Google adb tool
nexus-adb devices - command indicates I'm connected.
I push the Nethunter zip image to /sdcard/
I do Nexus-adb reboot recovery

I am dropped to black screen with icon and "no command"
I'm not given option to install

Questions:
1. prior to all of this do I have to unlock the boot loader?
2. do I have to root the device?
In any event the install is not working per the online instructions.
Any ideas or suggestions anyone?

Yes you need to root and unlock your bootloader