NOT A TEACHER
(1) I believe that it means that he had absolutely not (by any means) finished
everything that he wanted to do.
(2) I hear that certain world leaders (no names, of course) speak for 4 hours
to their people! If someone were to yell "OK, sir, that's enough" at the end of his
first hour, he would reply: I'm not done by any means. ( = I still have 3 more hours).
(Of course, that person who shouted out would be in BIG trouble.)
Student or Learner