No Honestly! stop laughing at the back there!

I was passing an instrument shop in Salzburg (which I can highly recommend) about a month ago and I bought a noseflute and a musical frog

I figured out the frog, but can't get a sound out of the flute.

It is made of wood and consists of a triangular bit formed from two pieces of wood with an airspace between them and a hole at the top then there is a rectangular block with a hole in it stuck on the back.

Any guidance gratefully received