To begin:
Plastic Parts and Features
PFTutorial.ipt, and orient the view to match the following image. 

Modify panel
Shell
. Do not remove any faces. For Thickness, enter 1.5 mm. Click OK to create. The following cutaway image shows the results of the shell operation. The cut is not part of the model.

Modify panel
Split
. In the dialog box, choose the Split Solid option. Select the surface named PartingSurface as the Split Tool. Click OK to finish. 
Notice that the part icon in the browser changed to represent a multi-body part. The Solid Bodies folder contains two bodies. You can right-click each body and select Properties from the context menu to set visibility or appearance.

Before proceeding, expand the Surface Bodies folder. and turn off the visible surface.
Save the file as PFTutorial_1.