Preferably soak the oats, raisins and seeds overnight in applejuice. In the morning grate the apple and add the apple and yoghurt to the soaked oat. Be careful with juice and yoghurt to start with, it's easy to add later. It will keep for 24 hours in the fridge.
I like to add nuts before eating, blueberries or raspberries are lovely with it as well, some people like it with honey or date syrup... You can keep adding and amending as you prefer it or depending on what you have.