Made this yesterday. It doesn't give how much of each to add, so add as much as you like, but would definately recommend it. Just had it for lunch.
I put 2 red onions, 1 white onion, 5 celery sticks, 1 tin of tomatoes, 1 tin of sliced carrots and then the rest. Could easily have chucked more in but didn't want to waste veg if I didn't like it