Measure the height of your shed door.
Cut a piece of piano hinge to the measurement that you took in Step 1.
Hold the piano hinge against the edge of the shed door and screw it on by driving small screws through the holes in the face of the piano hinge using the drill and appropriate bit. Be sure that the barrel of the piano hinge is facing the side of the door that you want to open out.
Position the door on the floor or ground with the side with the hinge on it located in the door frame. Shim the door off the floor or ground so it will swing free after you attach it. Screw the free side of the piano hinge into the door frame by driving small screws through the holes in the hinge with the drill.
Open and shut the shed door several times to ensure that it functions properly.