How to install Debian GNU/Linux system in quasi-remotely way

There's plenty of methods to install Linux system on a server. I'd like to present on of them which can be used when you have some restricted access to server (for example because you are ill and you are sitting in front of your computer inside of your home and you can only count on a person who is next to your server but he's, let's say, "computer idiot"). What can you do in this situation? Go through this simple step-by-step guide and the answer comes to your mind on its own.