How do you get puzzle 57 in professor layton the lost future?

Puzzle No 51:Park The Car.

Look for 3 hint coins, then speak to Barton and Inspector Chelmey,

Walk down and enter a door at the back, find 3 more hint coins by tapping on all the shelves.

Speak to Barton again.

Please see the related link below for a walkthrough of this puzzle.