Where to find a very straight forward tutorial to get X stations up and running Windows 10s with a single machine?

I have 1 spare HP DL360 G7 server, a Dell R420 with a lot of free resources, and a half-decent I5 with a R290X and 16gbs of ram, and Id like to use one of them to create something that allow my coworkers to have a working station they can use here without the need of a decent stand alone machine for each of them, and that they could also access from home, doing some remote access with their own PC for home working.

Currently Im using aster pro in a X desktop machine, I created 3 stations with it (the machine is on a table, and that big table got divided into 3 boxes, each one with 1 monitor, 1 kb, 1 mouse, 1 headphone...). Theres also 3 other coworkers that use another physical machines (terrible ones, with W10 in them) to access their desktops in this X machine and work from another rooms via Windows' own Remote Desktop Protocol (I had to mod the Windows 10 in order to manage multiple users using the machine at the same time, it disconnects the first user when a second user log in by default).

What Im looking for:

Something that:

- Allow all my coworkers a working station having only 1 physical machine
-Allow all my coworkers to access his desktop in this 1 physical machine from elsewhere via their own physical computers


I saw some kind of hardware that seems to be like a terminal where you connect monitor, kb, mouse, headsets... and this hardware is connected to the main machine via IP (an internal network?)... that was interesting, specially to solve the problem with the coworkers that are on different rooms and using mediocre machines to access theirs desktops in the main machine.

I also have a problem when the coworkers using RDP to access their desktops in the main machine needs to use VOIP: seems like theirs remote W10 desktops doesnt recognizes theirs headphones (they are headphones with built-in sound boards, usb ones). Theirs physical machines do recognize the headphones perfectly and they can to use VOIP software installed directly into the W10 in theirs physical machines, but they cant use the VOIP software inside their remote W10 desktops because it doesnt recognizes the headsets connected to the coworker's physical machine.

It may sound unbelievable but theres no one around here that seems to work with it, someone I could to hire to project and install such thing, and then to train me and my coworkers on how to use the whole thing. So I keep doing everything by myself, and having problems with some of the machines malfunctioning or the main machine getting fuc*** by some of the guys caughting a ransomware while looking for things I dont even dare to think about.

That post got a lot bigger than I expected, I hope you guys manage to figure out what Im in need... I dont know much about this subject so its hard to explain what I want, and my english is not better than my knowledge about multiple desktops...