You have selected this more than likely to keep pest out of certain rooms like pets or babies. This will more than likely be temporary if you are planning on buying a lock but in my perspective this works better than a lock because your door will not move when placed in and you do not have to screw anything in your wall tearing it up and there is no risk of it getting tore out of the wall because it is not screwed in to the wall.
There are other reasons to use this lock but note THIS LOCK IS ONLY FOR THE OUTSIDE OF YOUR DOOR TO KEEP THINGS/PEOPLE OR ANIMALS THAT CANNOT TAKE THE LOCK DOWN LIKE BABIES OR PETS.
You will need:
A metal piece at least 5 inches tall with 1 inch of the end bent at a 90 degree angle
A metal piece at least 1 inch in width and 3 inches tall (preferably) with a strip of something cut out of it
A screw 3 to 4 inches tall at least
Step 1: Step 1: Screw the Screw in the Metal Piece (Piece Not Bent "mine Is Bent But It Doesn't Matter)
You will need to take a small at least 3 inch tall and at least 1 inch wide piece of metal. Take it and drill a hole in the direct middle. Next take some type of screw or anything you can use as a screw and screw it into that hole. The screw must be at least 4 inches tall. Screw it about half way in leaving two inches on each side of the piece of metal.
Step 2: Step 2: Aligning the Door
Take the 90 degree piece of metal and align the 90 degree bent part with the door as seen in this image. Make sure you put it fairy high on the door especially if your trying to keep out babies, toddlers or kids. Make sure the piece of metal has a strip taken out in the middle like seen in the picture.
Take the metal with the screw in the middle and put the end of it inside the strip space in the metal in the door. You may have to twist the screw to tighten it to make it a tighter lock if it is loose.