When determining the opening direction, you should always stand with the door opening towards you (the side where you can see the hinges). Outward-opening doors are seen from the outside, whilst inward-opening doors are seen from the inside.
Right hand out - hinges located on the right side, seen from outside
Left hand out - hinges located on the left side, seen from outside
Right hand in - hinges located on the right side, seen from inside
Left hand in - hinges located on the left side, seen from inside
For double doors, the same opening directions apply, in that the door that opens first determines the opening direction, e.g. Right hand out = right door seen from outside opens first.
NB: The warranty does not apply to the tightness of inward-opening doors or inward-opening doors that are installed above ground floor level. An unfortunate combination of rain and strong winds from a particular direction can result in the ingress of water.