I used a drop shadow of vertical 0,  horizonal 5, opacity 55, blur 10.

Open a new transparent canvas 750 by 850 pixels and fill with white.

Paste element 2, resize 80%, position and apply the shadow.

Paste element 8, resize 50%, position below element 2 and apply the shadow.

Paste element 13, resize 50%, position and apply the shadow.

Paste element 3, resize 60%, position and apply the shadow.

Paste element 4 on the top, resize 65%, position and apply the shadow.

Paste one of the tubes, resize, position and apply the shadow.  I resized mine 40%.

Paste element 5, resize 75% and mirror, position below the window and apply the shadow.

Paste element 9, resize 40%, position and apply the shadow.

Paste element 17 above the window, resize 20%, position and apply the shadow.

Paste element 15, resize 30%, position and apply the shadow.

Paste element 26, resize 30%, position and apply the shadow.

Paste element 6, resize 30% and mirror, position and apply the shadow.

Paste element 18, resize 25%, position and apply the shadow.

Paste element 21, resize 25% and mirror, position and apply the shadow.

Paste element 19, resize 20%, position and apply the shadow.

Paste element 27 on the top, resize 30%, position and apply the shadow.

Paste element 20, resize 35%, position and apply the shadow.

Paste element 29, resize 23%, position and apply the shadow.

Paste element 25, resize 25%, position and apply the shadow.

Paste element 30, resize 18%, position and apply the shadow.

Check your layers now and make any adjustments.

Paste mask 342 above the white background, resize 85% and position.  Paste mask 363, resize 85% and position erasing the small part that shows below the house.  Pick a colour from the kit and use the Change to Target tool to recolour both the masks (for help with recolouring check out my Tips and Tricks Page).

When you are done, add your credit and text and export on a transparent background as a png.