OK, I am not going to re-invent the wheel. There are tons of free tutorials on the basics of Blender 3D.
As an Industrial or Product Designer, we do not really to know every aspects of Blender 3D.
The most important parts for us to know are:
1. How to use the interface.
2. How to import models from CAID programs into Blender 3D. This is covered in this website.
3. How to use Blender 3D to create photo-realistic renderings of the product designs. This also covered in this website.
To understand the interface of Blender 3D, the followings are links to useful tutorials:
Hope that these resources are useful for learning the basics of Blender 3D. 🙂