Here is a manual how to install the magnetic screen door:

 1. First clean your door frame well with alcohol or detergent. It must be dry.
2. Spread the screen door out on the floor with the velcro up.
3.Then attach the fitting part of the velcro strips in the small bag on the velcro sewed on the screen door.
4. Take off the paper from the sticky side of the velcro strip and hold it in the top in position on the door frame. If you got the height right, stick the long top velcro on the door frame (its recommended to get help doing it). Start in the middle and work your way outwards. Then both sides from top to bottom. Give it a little slack, so the magnets can close well.

5. If everything is in position, put pressure on the velcro strips so they stick well. Then use the push pins in the corners, in the middle on top and in between to reinforce (this is optional, depending what door frame material you have).