su working, visudo and sudoers missing, need install?

'su -' works properly but /etc/sudoers or /usr/local/etc/sudoers don't contain any files related to the sudo package. In fact, /usr/local/etc doesn't exist at all on this server. There are a pair of zones however and I need to manage security for the users. I believe I need to install sudo but I wanted to see if that is the right approach or if something else is needed. If I do need to install it, what's the recommended procedure?
thanks!