Bread is done.
I adjusted the recipe a little bit: my starter had a weight of 660 g, so I increased the total amount of flour and water (proportional to mihl's recipe). And after one hour added a tiny bit of yeast to the dough (you can do that with a new sourdough) cause it hadn't risen at all.
I just tried my first piece of bread and it was so worth the effort. I'm so gonna start sourdoughing as soon as we're settled!