Hold the battery pouch between your thumb and finger and gently press the card together so that the copper tape is touching both sides of the battery.
Take the LED and place each leg on a copper strip on the outside of the larger side. remember the longer leg needs to be touching the copper tape that is touching the positive side of the battery,
When the LED lights up you know which way to attach it.
Use the double sided foam and stick the pins of the LED to the copper tape.
Bend the LED gently forward so that it is at a right angle to the card, facing the same direction as the foam tape.