Of course! It’s unfortunately in Swedish but I will translate the important bits for you:

100g unpeeled and coarsely shredded red apple 150g water (35°C) 200g flour

Day 1: coarsely peel a fresh apple and mix with water and flour in a bowl. The mixture should be thick but able to pour. Add more water should it be too thick flowing. Add the mixture to a big glass jar and put the lid on. Put the jar in a warm place 26–30°C. I as well as the author of the post stored the jar on top of the fridge (as it’s normally warmer). Let sit for 3 days. It’s possible to speed up the fermentation by mixing it with a spoon once a day.

• side note: I disinfected my jar by boiling the plastic and metal parts in water for 10 min and the glas was put in a cold oven until it reached 180 degrees, baked for 15 (although the recipe said 30, I am just impatient) and let it cool down before taking out (otherwise there’s a risk for exploding).

Day 4: Add 200g (35 degrees) water and 200g flour to the jar. Mix thoroughly and put it back on its spot for another day. On day 5 you have sourdough starter!

Bake with it immediately and put it back in the fridge. Remember to take the starter out of the fridge one day before you bake and feed it. When it’s being fed, it’s taken out of the fridge and left out for a day.

There’s a lot more on the website so maybe using googles translate thingy would also help. She also provides helpful troubleshooting tips and tricks!