https://github.com/mediabots/Linux-to-Windows-with-QEMU

Requirements
A SSH client such as Putty : https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html
A VNC software such as RealVNC : https://www.realvnc.com/en/connect/download/viewer/
A VPS or Dedicated server with Ubuntu OS Installed.

At least 30GB Free disk space in your system.
Virtualization of your VPS or Server must be enabled. Run below coammnd :

echo $(egrep '^flags.*(vmx|svm)' /proc/cpuinfo | wc -l)

if output is greater than 0, then Virtualization is enabled :D

Either should have access of root user OR run with su (super user)
Optional

If you want to use your own Windows ISO copy.

Then download official copy from https://www.microsoft.com/en-in/evalcenter/evaluate-windows-server-2012-r2 and upload it to your extra server & create a direct url and then replace LINE NO. 39 & 41 of mediabots_Ubuntu-to-Windows.sh with your DIRECT LINK

Script Line No. 39 :-
sudo wget -P /mediabots http://51.15.226.83/WS2012R2.ISO

Script Line No. 41 :-
sudo wget -P /mediabots https://ia601506.us.archive.org/4/items/WS2012R2/WS2012R2.ISO
How to Run the Script

Befor install windows update your ubuntu:
apt update
apt upgrade

Just run below five commands one after another :
su
mkdir /media/script && mount -t tmpfs -o size=1m tmpfs /media/script
wget -P /media/script https://raw.githubusercontent.com/mediabots/Linux-to-Windows-with-QEMU/master/mediabots_Linux-to-Windows.sh
chmod +x /media/script/*
/media/script/mediabots_Linux-to-Windows.sh