Notice the tone holes increase in size.  That is the elegance of simplicity, the wonderful marriage of science and art.  With the four holes, you can go from do to do and, by SLIDING your fingers gradually off the holes, cover each and every frequency between.   With all the holes open, blow into the whistle only enough to make a clear tone, not too forcefully nor too timidly.  Now, cover the holes completely and slowly slide your fingers off while you blow, then slide them back over the holes.  Now try it again and say "tu-tu" while you do it.  Practice, practice, practice.  The "tu-tu" part is a basic wind instrument technique that will give you the breaks between the notes.  Scroll the page down for scale charts, including the Western Scale (do-re-mi-fa-sol-la-ti-do) and several others.  Notice the fingering for the Wearable Mini-Ocarinas, Bear Paw Ocarinas (Paint and Play) and the "Traditional Model" (Including the Zelda Replicas) are the same.