Lesson 2-01-03 - Low E
Low E is one of the eight simple low notes (along with D, F#,G, A, B, C natural, and C sharp).
It is made by covering the top five holes, leaving the bottom hole uncovered, and blowing softly into the mouthpiece.
It is a little easier to play than D, owing to a bit more give with the breath control, and most whistle players can manage a clear E after some practice.
This should be one of the first notes you learn after you master B, A, and G.