Go upstairs after entering to get a fair overview of this locale. Once you gain control of Link, use the Beetle and look atop the entrance pillars; one has a Red Rupee atop it.
Goddess Cube 7
Go forward to the crest at the nearby altar. Ignore it for the moment and go around behind it to find Goddess Cube 7. Hit it with a Skyward Strike, then return to the platform in front of the crest. Hit this with a Skyward Strike. You’ll watch a scene, during which you’ll obtain the Ruby Tablet before automatically exiting to the Deep Woods.
One dungeon down, it seems. Upon exiting, go forward and you’ll converse briefly with a Kikwi. Afterwards, use the Bird Statue to save and return to the sky.