Clarification between Technician and Reference computer

Folks:

I am reading the Installing and Configuring Windows Server 2012 Training Guide; however, I am having problems understanding what I am learning starting on page 47 and for roughly the next 20 pages detailing deployment from reference images.

Specifically – is the Technician computer where I build the image – meaning it is the source machine that I install and configure how I want my image to be, and then migrate it over to the Reference machine – then back to the Technician machines?

What is the Reference machine providing when the book says “This reference computer must be a bare-metal system”? Unfortunately I do not have the resource to practice doing these exercises yet, so I am a little confused.

Thanks you

JJ