Error when building nvidia-smi

I am new to using ubuntu so this may be a simple question answered, However I was running the linked code for installing the NGC but after running the first few lines of code provided, running nvidia-smi came up with nothing.

So i tried going through the steps once more and i see an error that says:

0 upgraded, 19 newly installed, 0 to remove and 255 not upgraded.
Need to get 4,217 kB/86.4 MB of archives.
After this operation, 406 MB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
nvidia-387 nvidia-387-dev libcuda1-387 nvidia-modprobe libxnvctrl0
nvidia-settings nvidia-opencl-icd-387 cuda-drivers
E: There were unauthenticated packages and -y was used without --allow-unauthenticated
:~ :~
:~$ Read more at:
No command ‘Read’ found, did you mean:
Command ‘head’ from package ‘coreutils’ (main)
Read: command not found

I am not sure how to proceed

Is it possible that you forgot the ‘apt-key add’ step from ? Be sure to run ‘apt-get update’ again after installing the key, also.

That is, to just add the key right after the “-” in
apt-key add -#####################

that gave me a gpg: conflicting commands
(23) Failed writing body


The hyphen at the end tells apt-key to read the key from stdin. Please see man apt-key for details.