I have installed Windows 2016 in a PC. We have an isolated network with about 25 PC's. I want to be able to use one of those 25 PC's to perform maintenance functions on the remaining PC's - using the PC with the Windows 2016. I don't know how. Does anyone know what the best training courses would be to help me learn how to set that up, and make that work?

Never heard of windows 2016 before. And I've used every version of windows that existed since windows 286. (Before windows 3.0)

I think the OP means Server 2016.
Either way they'd need SCCM, a domain and probably more knowledge than they currently possess..