You can buy the whole assembly from smart as follows:

Start by choosing the location you want to fit the CD holder in the centre console.

Removing the accessory that is in the way. The shelves simply pull out.

In the space left, you need to fit each CD tray one at a time.

The complete assembly for this installation consists of 3 CD trays and 1 drinks holder. The insert for the drinks holder actually fits into a CD holder frame. This can easily be removed making four CD holders if you wish.

For the ones you can get to, bend the back of tray runner as shown below, and push in place. Ensure that you get the finger tabs correct! For the shelf on the bottom, the tab needs to be on the left; for the one at the top, it needs to be on the right.

If you have a shelf accessory above where you are fitting the CD trays, remove that as well as it will make fitting the last tray a bit easier. If you can't do this, you need to slide the draw in with the CD tray slid out. Hold the frame and wiggle it back until it clips in place.