This is not a tutorial, it's more of a note so I'm going to remember how to do something the next time I stumble again on the same problem.
When you need to perform a task on your Mac that requires a Windows machine your choices are three:
1. Virtualization (Virtual Machine,..)
2. Dual Boot
3. Using two computers
Excluding the third options which we're not going to cover for obvious reasons the choice is pretty obvious. Virtual Machines are fine if you just need to do quick tasks, but at times you need the actual machine without the complexity of a hidden VM on top. Luckily Mac's support for installing Windows alongside OSX is great.
The installation process is annoying, but once installed simply holding alt while booting lets you choose which OS to boot up to.
1. Get a windows iso
2. Open boot camp assist, partition the drive as you wish (you should give the windows partition at least 50 GB to be sort of usable, probably more), insert a USB stick and start the process
3. Reboot to the empty partition and install windows from the USB stick.
4. Reboot back to mac and get window support software for Bootcamp.
5. Don't download it from google. Open Bootcamp assist from Mac -> Action -> Download Window Support software.
6. Copy it onto a USB stick, reboot to windows and install.
7. Once on Windows remember to run the Apple Updater application every once in a while.