First of all you need to install the Mockup Plugin. This plugin needed for 3d transformation of your design.

Paste your image/content inside ‘Paste Here’ frame.

From top menu launch Mockup plugin

Click on the Distort tab.

Find a layer called "Change This" and select it. This will be set as a target for your mockup.

Now choose a 'Paste here' frame (this will be used as a source) and click on Apply button. You may also need to increase resolution or rotate a direction.

Some scenes are also contains Clay version (or Changeable Color). That's a beautiful and popular clay stylisations. You can color device as you like.

To do so you need select a "Change Color" layer. Open fill color and choose any color or gradient that you like
