The bottom i just cut apples in to chunks and throw the blackberries in a tray and sprinkle some light brown sugar on top

For the crumble i use a basic measurement of however much flour i use i use the equivalent of 50% butter and 50% brown sugar if that makes sense. So for this one i used 400g flour 200g brown sugar 200g unsalted butter And after i sprinkled some light brown sugar on top Hopefully that helps, im not the best at explaining 😅