SolidWorks Tips and Tricks Series: Plane creation
Click on the Top Plane and make the plane visible as shown below.
To quickly make an Offset Plane, or Copy a reference plane, you can use the standard Windows method for creating a copy: Hold down Ctrl (Control) and drag/drop. Select or show an existing reference plane. Hold down your Ctrl key and click/drag on the edge of the plane. You’re automatically entered into the Property Manager for defining an Offset Plane.
Now select the desired parameters and the plane is created as shown in the below image.