To the East of Neftak Outoust is a broken bridge, To the West of the Southern side of the broken bridge is a sloping lump of broken masonary.
Start the quest and pop the 3 green bubbles by jumping through them and hand in on the north broken bridge.
Hint1: wear your jumping gear. Hint 2: Invisible platforms. PS: you can climb up the left side of the northern bank.

I used [Take Off!] Lightstone Set (Rush x2 + Feather x2) + Black Magic Crystal - Ascension x2 + Elixir of Wings + Stir-fried Vegetable video

This video may help too