cut down the hanging chest in the middle room with the gale boomarang
Death Mountain
After you complete the Forest Temple the twilight is no longer in that region and Link must travel to the next region of Hyrule to rid it of the twilight
the forest temple
It's on the map.
beat the boss
When you get compass it will tell you the location of the monkeys
The big key
get the boomerang.
You finish off the forest temple mini boss
Use MyCheats . com - there is a full video walkthrough.
In Twilight Princess, the only monkey whose name is given is the forest temple boss monkey - his name is Ook.
as soon as you defeat the Minny Boss in the Forest Temple you get the boomerang