Firstly, design a 3D model of paper craft you wish by using 3D CG software.

In Pepakura Designer, the following file formats are supported:

3DS, DXF, MQO, LWO, OBJ, STL, KML, KMZ

(You should prepare 3D CG software separately.)

Load the created 3D data into Pepakura Designer.

Push Unfold button and create a development.

Edit the development in order to make the construction effortlessly.

Lastly print and assemble them.