Sorcha -

Most of them are about the size of a Bb p'whistle.(?)

LeS -

The technique often suggested is to place the mouthpiece on your lower lip, about where the "pink" turns to skin. The hole in the mouthpiecs should be pointing just about straight up. Blow at (not into) the hole, and then roll/pivot the thing "up and down" on your lip until you "find the spot." Once found, it's usually pretty easy to capture the feel of it.

John