I have made a video tutorial displaying and explaining how to set up an Arma3 dedicated server.
It may help users that are a bit more reliant direct visual input on where to do what when and why.
Here is a link to the video :
https://youtu.be/S_w17e26vL0
Hopefully this will help for those who get stuck a little.
EDIT: Also contains troubleshooting for extremely common errors / issues