When you stand in front of your car looking to the engine, you will see it at the right side of the engine, in line with the front of the engine. It is completely round of shape (round ca. 10cm), has a round lid and a black plastic mutter on top; you can't miss it.
On the picture below:
you will see some sides of the round lid under the bended water hose at the left side of the air intake hose.
good luck and greetingz,