Overview
I`ll be explaining how to beat each puzzle on 3rd island.
Water puzzle
First you need to complete a side quest by looking for the crab that`s at the beggining of the path that leads to the air puzzle. He will ask you to deliver a huge coconut to some other crab that is at the left end of the beach.
He wil give 3 leafs.
You will need 2 leafs that you will give to the Vodoo crab that is located just a bit north of the yellow one, in this area:
He will give you the Tomahawk which will help you with the gigantic log at the water puzzle.
You can also upgrade your boomerang here.
Fire puzzle
Get one wood log from the water puzzle and deliver it to the yellow crab.
He will give you an unlit torch which you will use to lit all the torch thingies at the fire puzzle.
Once lit the torch have a duration of 4 seconds or so before it goes off so you might have to throw it a bit pick it and and lit the thinghies. Be quick tho.
Air puzzle
Avoid the smoke thingies by rushing to the safe zones and once you reach the puzzle, move the air blowing stones like this:
Earth puzzle
The earth one is the most simple one.
All you have to do is get a stone, a wood log and a leaf and put them on the corresponding stones.
Yeah, there is a bit of back-tracking on this one.