If you are not at home at the time of delivery, the parcel will be dropped off at the nearest postal point. Via the track and trace system, you can always find out at which exact postal point the parcel was delivered.
You can also always leave a note on the door with a message to the courier. They will then always try to comply with your wishes. For example, you can mention that the parcel can be left in a safe place or left with the neighbours.