The Nomad's directions are as follows....
Leave the Nomad's camp and head toward the desert in the west.
Upon entering the desert, head to the west. You'll eventually come across the three boulders the Nomads were talking about. Walk south from the boulders.
You will eventually run into the snake-like rock formation. From here walk northwest.
These are the "dragon skulls" the Nomads were talking about. Walk north past the skulls. You will eventually run into a large skull. Enter the skull through it's mouth and you will exit Taklama. If you never see the large skull, just continue north for a ways and if the skull still doesn't show up, head to the west. Most likely you'll exit out of Taklama at the correct end.