Can't install any apk to Air Unit

I need help to install my custom app to AirUnit.
I followed some tutorials about it like “adb install myapp.apk” but I got “/system/bin/sh: cmd: not found” error.
Is there any idea to create a autostart script or install custom application to Air Unit?

Have you installed the ADB tools?

Thank you for your reply,
I installed ADB tools and tried different SDK versions. But it can’t help me.

Does any device show up when entering adb devices ?
Also, have you turned on the developer mode?