Before you say hang on theres only one instrument of time the ocarina! well your wrong with links new forms along come new instruments. Deku link has organ pipes, goran link has the bongos and zora link has the guitar
When you play the song of time in this game you will return to the 1st day when the moon begins to fall. So you wont get smushed after all!
There are many other uses for the instruments. Almost all temples are opened by them.
Be sure to talk to the scarecrow in the observatory to learn how to slow time, speed time and skip a day . All very usefull to help get all the masks you need
Here are all the songs...... 
The song of time will send you back to the 1st day (note:this is needed to be taught before it works). The inverted song of time will slow time down (dont worry nothing goes in slow-mo just gives you longer) and the song of double time skips a day.
Note: most songs you need to be taught so they can take effect. The two above (not the song of time) do not need to be taught and are secret songs in the game
