Making it up as we go along

[Eulaliaaa!]

Clean off the electronic device as best as possible, inspect it.

[Lord Daskar]

Eat the device!

[Aimless Gallivanter]

Young Matthew wipes his mouth and goes back to the edge of the beach where he spat out the beetle and the electronic device. It's gone. It seems the waves has washed it away already.

The boy wanders off down the beach. He prods the coconut with a bare toe, and crab scuttles away. A bird appears out of no where and snags it, before flying off into the trees. Staring after it, he notices a volcano.

[Groddil]

He uses a rock to break the coconut in half, carve two eyes holes in it, then he wears it like a mask and chants: "Unga Bunga!" in tribute to the Volcano God.

[Chipster of Noonvale]

...

[Hickory]

Electronic devices don't fare so well in water. Volcanic soil is a fertile type and usually has plenty of life growing in it, you can head there for more food.

[Søren]

Electronic devices don't fare so well in water. Volcanic soil is a fertile type and usually has plenty of life growing in it, you can head there for more food.

[Jetthebinturong]

He uses a rock to break the coconut in half, carve two eyes holes in it, then he wears it like a mask and chants: "Unga Bunga!" in tribute to the Volcano God.

[Lord Daskar]

He uses a rock to break the coconut in half, carve two eyes holes in it, then he wears it like a mask and chants: "Unga Bunga!" in tribute to the Volcano God.

[Aimless Gallivanter]

Matthew picks up the coconut and heads up the beach to the rocks. By chucking the coconut at the rock face several times, he finally splits it open. He scoops the contents out with a seashell, but nothing he can find is sharp enough to make eye holes. He holds half of it to his face anyway. "Unga Bunga," he says hollowly.
"Unga Bunga."
The Volcano Gods rumble in appreciation. They will watch over this resourceful new follower, they decide.
Matthew panics when the volcano rumbles. He chucks the pitiful coconut mask into the jungle before running into the ocean to get as far from the volcano as he can. The Volcano Gods accept his offering of one (1) half of a coconut. They do wish he'd try a little harder to actually get it in the volcano next time.

[Fatch of Southsward]

  Okay Hahahahaaaa!!!!  I'm dying at what just happened! 

As for what he should do next perhaps while he is already in the ocean he should...

Try to make contact with the dolphins to find out where he is stranded

[Jetthebinturong]

Try to make contact with the dolphins to find out where he is stranded

[Hickory]

Swim out a bit, scope out the size of the island.

[Chipster of Noonvale]

...

[Søren]

Try to make contact with the dolphins to find out where he is stranded