How does fortnite work on windows 7?

How can I install this

Download and install.

There's certainly a tutorial on Youtube.

Yes indeed:

But there's owned

First install Epic on: https://www.epicgames.com/.../store/de/

At the top right is a button to install it

You would also have to register but you can also sign up via XBox or PS4.

After you have installed it you have to simply click on Library and then on the Install button that is under Fortnite, as soon as you have it installed there's then a button with "Play", as soon as you pressed it you can play.

But there's in possession

If you go to library there should be a start button right? If there's only in possession you can try to restart your game

Now only a tutorial is missing, how to watch a video on Youtube.