Junior Sys Admin planning to set up a Windows Server with MDT for our techs to reimage some 200+ assets in our network on a time crunch. Need some help understanding the networking behind this.

So the official guides from my organization describe this as a system (talking about the deployment server) that will be physically connected to the network, but not on the domain. It is supposed to be able to deploy this new OS Image remotely to any computer on the campus as long as it is plugged in. As I said, I am very junior, and still learning the ins-and-outs of networking and its particulars. Can someone help me understand how this will work? How can this server possibly communicate with all of these functioning desktops and laptops on the network if it is not on the same domain? Seems to go against everything I've learned and observed about how domains work. I'm not even sure if I am asking the right questions, and there is no "senior" person in my role within the organization at present for me to ask specifics, so I'm kind of leading the charge and working from the ground up for the role.