The tutorial emphasizes a four-step process: first, creating 2D sketches on a chosen plane; second, extruding the sketch to add volume, making it 3D; third, sketching additional features on selected faces; and fourth, extruding these features to modify the initial object. The tutorial also covers basic Onshape interface navigation, including selecting and deselecting objects, changing views, and using tools to define dimensions and shapes like rectangles and circles, culminating in the creation of a simple 3D box with a hole. 

This video shows the process of 3D modeling and printing a cube using CAD software. First, a 2D sketch of the cube's face is created and measured. Then, this sketch is extruded to form a 3D model, which is exported as an STL file. Finally, the STL file is imported into slicing software (3D printer OS in this case), where settings like layer height and infill density are adjusted before initiating the 3D printing process. It also briefly discusses different types of 3D printers and their associated slicing software. Different units of measurement are also addressed.