I only soak oats if I am not going to cook them. For instance, I do a variation on the original Bircher muesli, which is oats soaked overnight, served with chopped apple and yogurt.
If you are cooking the oats to make porridge, I don't know why you would need to soak them. Just follow the proportions of oats to milk or water on the packet and microwave (usually for about 3 minutes, but it depends on the microwave power).