How do I make a list?

I’ve been search and searching and can’t find instructions on how to simply make a list of email addresses, and send my newsletter one time. I tried adding a list of addresses using a comma delimiter in the first box of the Lists page in the dashboard, but it wasn’t recognized as a list, so that wasn’t the answer. Could anyone please help me to find how to do this? As I said, all the instructions I can find are about managing subscription lists and that sort of thing. I really just want to use the plug in to send attractive newsletter style emails if and when I choose, I don’t want any automated emails or anything like that. Thank you for your help!