Getting started

When you first open Blender, your brand new project always starts with three objects—a camera, a lamp, and a default cube. Cameras and lamps are more applicable to modeling for animations and videos than they are for 3D printing, but there is no harm in leaving them in your project. The default cube, however, is not going to be necessary for our pendant and will just clutter up the screen:

Three default objects for every Blender project—a camera, a cube, and a lamp

The first thing you'll want to do is delete the unnecessary cube with the following steps:

1. Right-click the cube to select it. You will see the cube highlighted in yellow and a trio of axis arrows originating from the center of the cube.
2. Along the left side of your screen is an area called the Tool Shelf. If necessary, select the Tools tab. 
3. Under the Edit section, hit the Delete button. Alternatively, you can hit the Delete key on your keyboard.
4. A popup menu will ask you to confirm. Click Delete or hit the Enter key:

Deleting the default cube