[K12OSN] Using Yum - Help

[Mark Sarria]

I am trying to us yum to download and install updates for samba, and
smbldap-tools. I might be using incorrectly, this is what I enter in the
prompt:
# yum update 

Then I get this message:
You have enabled checking  of packages via GPG keys. This is a good thing.
However, you do not have any GPG public keys installed. You need to download
the keys for packages you wish to install and install them. You can do that
by running the command: rpm --import public.gpg.key
For more information....

I am I missing something, or better yet ,can someone educate me on the
proper use of yum, for updates.

Thank you for your help

--mark