Hello roman48tdr,
Drive AGX platform has a completely different software stack and a more complex one than the Jetson family platforms.
That said, it is expected that provisioning the Drive Software consists of a different procedure that has multiple gentle steps.
SDK Manager simplifies it for the user in case a flashing of the original package as-is is needed.
We do appreciate feedback on our documentation, as it is improving in every software release. So it is helpful to understand your specific needs (that are probably shared by others) and see how to improve our documentation if needed.
Answering your questions:
please refer to here: (this part of the documentation will be removed next release)
7z-files-not-found-for-command-line-install
for the initial installation of the Drive Software and flashing of the board the right procedure is to use SDK Manager (documentation is here)
for flashing from the command line using Drive scripts please refer to Flashing Basics documentation here
for flashing customization please refer to the documentation here
good luck