Lesson 2-1-5 - Low F Sharp
Low F# is one of the eight simple low notes (along with D, E, G, A, B, C natural, and C sharp).
It is made by covering the top four holes, leaving the bottom two holes uncovered, and blowing softly into the mouthpiece.
It is a little easier to play than D, and comparable enough to playing an E note.
As it's usually the fourth low note you learn after you master B, A, and G, beginners often have some trouble with this because they don't cover the 4th hole properly with the right index finger. The trick is to grip it very tightly, and ensure that the finger is properly covering the hole.