The left wheel cycles through the three colors of light coming from ONLY the statue right in front of you. You can continuously turn the wheel to cycle through the colors to get the color of light you need for that statue.

The right wheel only rotates the entire assembly and does nothing else.

You'll want to make sure you've rotated the wheel to each statue and chosen the right color for it and once they all have their proper colors, rotate the entire assemble to the proper position.

For clues on the correct light colors and correct position of the statues make sure to take a close look at the sarcophagus and the symbols on the sarcophagus.

Tex's instructions for this one are a little confusing, so let me rephrase.

Each statue is carrying a sign that tells you what element it represents. The first thing you need to do is change the light on each statue so it matches that element.

Blue for water and yellow for sun are obvious; red for earth isn't quite as obvious, but it's the only color left, so red for earth it is.

The large wheel on the right moves the statues around in a circle; the wheel on the left changes the color of the light on the statue nearest to the right wheel.

So look at the sign held by the statue hit by the light from the ceiling (it's the one closest to the door you came in by). If it matches, you're good; if it doesn't, turn the left wheel to change the light until it's right. Then turn the right wheel to move on to the next statue.

When all the statues have the right color light, continue moving the right wheel until the elements of the statues match the symbol on the central stone box. When that happens, it slides aside to reveal a hole in the floor. Jump down to move on to the next area.