HOW DO I NAVIGATE THE TUNNELS?

First of all, you'll need some light and protection.

Luckily both are readily available.

Take the torch and dagger on the wall (one is in front of you, the other behind you) and step into the darkness.

Now it's just a matter of navigating the maze.

You just so happen to have a map on you.

Examine the dagger you took from the wall.

Follow the dotted line from the circle to the X.

Starting from the central circle go left, up, left, down, right and up.