This page of the guide to Immortals Fenyx Rising contains a map showing the location of every Ambrosia located in the Gates of Tartaros region.
You can find Ambrosia in 7 places in this region. The resource will be quite easy to obtain in most cases; you will often find the Ambrosia high in the mountains, or right in the open. Some are also found on remote, small islands.
1 - The Tartaros mountain
Ambrosia is located on the Tartaros mountain. From there, you'll also be able to discover the entire region.
2-The Tartaros mountain summit.
Just like the previous Ambrosia, this one is located on high ground, at the very top of the Tartaros mountain.
3 - The mountain peak by the vault
Near the inside of the Vault of Typhon, there is a mountain peak to the right. That's where Ambrosia is.
4 - The red lake
Ambrosia is located near the Tartaros mountain, at the very bottom. That's where the red lake is, and Ambrosia can be found nearby.
5 - The hill in the north
In the northern part of the region, there is a hill in the middle of the lake. Ambrosia is exactly on that hill.
6 - The hill near the wall
There is a body of water near the wall, neighbored by a few mountains. Ambrosia is on one of the lower mountains.
7 - The Wall
On the wall, there is a lever which opens the door to the Ambrosia. Activate it, then quickly fly towards Ambrosia, because the door is only open for a short while.