Unfortunately, you will have to do a lot of tweaking a lot to get it to usable level. You won’t have any start menus, taskbars, GUI-based settings, or any clickable buttons outside of the program you are running right off the bat. These are intended to be filled in with programs of your own choice, but it won’t be shipped with Hyprland.

Or do I have to install extra extensions or have to muck around in the config to have a proper desktop?

Yes, that is the case. It’s what makes it attractive for those who want maximum customisability, even if it takes a long time to get there.