After entering and regaining control, use the nearby Bird Statue to save, then follow the path downstairs.
As you go down, you’ll encounter a few spider webs; you’ll need to cut them down, as well as the Keese and trees in the area. At the end of the path, you’ll find another grouping of trees. Cut them down and back up some.
On the ledge above, there is a Deku Baba (a species of carnivorous plant that are famous for their short temper & feisty attitude) and if you take the more obvious method, you are going to get hurt.
So, as I said, back up and shoot at the crystal switch with the Slingshot and the door nearby should open up. Go in there.
Go up the nearby staircase to a higher central platform. As you do, an eye will open above the northern locked door. Withdraw your Goddess Sword.
Seeing as the eye will follow your blade’s tip (remind you of the Mr. I (or whatever it was) from Super Mario 64?), you can move your sword in a circle a few times. The eye will redden and die, also opening up the door. Go through the next room.
Here, you’ll find some Deku Babas hanging from the roof, as well as some spiky ticking bombs in the grass. Defeat the enemies and proceed forward to the bulk of the room, where you’ll find a Bird Statue.
Save your game, then do a 180 and shoot down the spiders (Walltulas) on the walls. Climb up these vines to the alcove above, where you can cut down the boards here for a future shortcut. Return to the previous room.
Go to the central portion of the room and slice up the Bokoblin there. The three doors here are locked; look at the eastern one and up to find a crystal switch. Shoot it to open the door and go through.
In here, proceed forward and cut down the spider web. Drop the lower area of the room further ahead and examine the eastern wall (remember, my directions are usually MAP-based) for a bit.
Once you find the tunnel, crawl through to the statue and shoot the crystal switch it is “holding” to fill up the rooms with a bit of water.
Swim over to the vine curtain nearby and go up. Enter the tunnel and exit into the previous area, then continue to the middle room.
South Room (Again)
Here, go towards the western door. It is still locked. However, we now can UN-lock it. Get into the water and swim beneath the bridge connecting the central platform with the western door.
Nearby should be a crystal switch. Get onto the platform and hit it, thereby opening the western door. Swim out from under the archway, ascend the vines, and go through the newly-opened doorway.
In this room, you’ll find two Skulltulas hanging from their vines on the main bridge. Trust me when I say you will not want to cut these webs down - these Skulltulas can become a huge pain, and rather scary as they can get tough to defeat off of the webs.
Head to the western side of the room (map-based - I have to drill that into you!) and look up. You’ll find two curled-up vines; shoot them both with the Slingshot to make them usable. Use them to go across the gap safely.
On the other side, defeat the Quadro-Baba and ascend the nearby stairway. Go through the door.
South Room (Yet Again)
Go up this path to find a chest, in which you’ll find the Dungeon Map.