Disregard. Thanks to all who have looked at this. I found the answer in nano; not sudo. I am editing the file now.
My screen shows me@ubuntu-server:$
I typed the following after the $ sign:
-bash /etc/network/interfaces: Permission Denied
When I installed the server I was prompted to input a username and password. I did. Am I--the user--not the administrator? Do I need to sign in as root?
I tried also entering: sudo /etc/network/interfaces to no avail.