What am I supposed to do in Sitnalta?

Hint 1 of 16:

Have you been to the Mer City yet?
There are several hints to help you there.

Hint 2 of 16:

For one, follow the mermaid into her room.

Hint 3 of 16:

Then go into the museum and read the plaque.

Hint 4 of 16:

You will have to find the four seahorses and put them back where they belong.
The location of those horses is covered in the next question.

Hint 5 of 16:

It might help to map out the area first.  Make note of its size and any
interesting locations.

Hint 6 of 16:

The scroll you found underwater would be a perfect match for the map, if you
drew a 9x4 grid over it.

Hint 7 of 16:

You will need to follow the path drawn on the map, exactly as it is shown.