This lever can be found on the Right side of the steering wheel.
Follow these steps to turn it on:
Push the lever down once (slow intervals)
Push the lever down twice (fast intervals)
Push the lever down thrice (very fast intervals)
Follow these steps to turn it off:
Push it back all the way up to its original position
To activate the wiper at the back, turn the small knob on the right side of the lever up once for rear washer and wiper speed, and the other direction to "On". Remember to switch this off once you are done.
To spray the water jet onto the windscreen, pull the same lever towards you.