The file is intended for Adobe Photoshop CC 2015 – CC 2019 versions.
3D function in Photoshop should be enabled.
The mockup includes special layers and 3D elements. Regular design layer also included.
You can download a free Snack Package Mockup to check how it works.
Here you can see How to edit Mockups with 3D smart layer: step by step guide.
Sample design is not included in the download file