The moment you arrive, Sora immediately realizes that he's alone, with Donald and Goofy missing. Once you regain control, you'll be fighting a leopard, which should be easy enough. After the battle, you'll have to watch some long cut-scenes -- the first one between Tarzan and Sora, the other between Donald and Goofy. Tarzan will now be in your party. Just drop off the side of the tree house when you regain control. In the next area, jump on the platforms to your right for a Mega-Ether.
There's also a save point here, so save if you like. Drop off the hole to your left to the next area. Avoid the branches here by jumping past them, you'll be at the Camp after that. Go into the Tent for a cut-scene, where Sora finally meets up with his two companions. Save your game and open the chest here for a Mythril Shard. Speak to Jane here and she will ask you to help find the slides so exit the Tent to begin your search. Outside, you can activate the Blue Trinity mark located near the exit that leads to Hippo's Lagoon to secure Puppies 34-36.
Here are the locations of all the slides:
Slide 1: Find it on top of the Tent you exited from.
Slide 2: Go left from the Tent and find it on a file cabinet at the end.
Slide 3: Find it in front of the painting canvas.
Slide 4: Jump on the stack of boxes north of the Tent to get it.
Slide 5: Find it on top of the brown tent. Walk to the end.
Slide 6: Climb the set of boxes at the right side of the Tent.
Once you're done, go back inside the Tent and examine the projector to view the slides. There'll be a cut-scene, where Clayton asks Tarzan to take him to the gorillas. Leave the Tent and go south to the Bamboo Thicket. In the next area keep going north until you reach the Cliffs. Here, jump on the rocks to your right, climb the vines and go left for 2 chests with a Mythril Shard and a Mega-Potion. Head back to Camp and this time take the west exit to Hippo's Lagoon. There's a vine to your left that leads to the next area, but don't climb it yet, instead jump on the pink platform on the water and go north. There's a chest at the end with Puppies 25-27. Go back and climb the vine.
There's another save point here. Just swing through the vines until you reach Vines 2. You can go up the vine immediately to proceed to the next area, but be sure to jump on the vines here to get a chest with Puppies 28-30. Here, proceed to the Tree House, activate the Blue Trinity mark first to get Puppies 31-33. Go in. After the cut-scene, head back to Camp and into the Tent for another cut-scene. Leave the Tent, and you'll be fighting your first batch of Power Wilds. Basically, what you have to do is: rid every area of Heartless. You'll receive items from the gorillas each time too.
Once you've cleared each area, go back to Camp and talk to Jane. (Don't forget to save) Proceed to the Bamboo Thicket and after a short cut-scene, you'll have to fight Sabor. This one's easy -- attack it and roll out of the way once it charges at you. You'll receive 150p and a White Fang accessory.
There'll be a cut-scene. When you regain control, head back to Camp and Jane will be missing. Save your game and proceed to the Tree House. Don't bother trying to kill all the Heartless here, since they'll just keep coming. Your target is the black thing, just attack it several times. Head back to Camp and save your game. Proceed to the Cliff. After a short cut-scene, you'll fight Clayton. Just smack him around a bit and he'll summon Stealth Sneak after a while.
This battle isn't that hard. If you have a decent amount of MP try hitting Stealth Sneak with whatever magic you have, but be sure to move in for some close combat as well. Keep in mind that Clayton will also be shooting you with his rifle, so roll away when you see him aim. Once Stealth Sneak's HP is down to the green bar, Clayton will fall off. This time concentrate on Clayton, don't bother with his chameleon. Just dodge whenever he fires his rifle, and attack him with all you got.
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After the battle there'll be a cut-scene and you'll also learn Cure. When you regain control, go into the cave. Your only way here is up, so climb while opening treasure chests with a Mythril Shard, Shell-G, Mythril and Orihalcum along the way, until you reach another cave labeled "???".
Go inside for a cut-scene and you'll get a Navi-G Piece. After that, you'll see another cut-scene, this time between Jafar and Maleficent. Then you'll get the Jungle King keyblade from Tarzan.
There is also a mega-potion in the beginning on a ledge above the netting under the treehouse before you drop off.