Now, try closing the card. Your LEDs should light up!
Sometimes, not all of your lights will light up at the same time. That’s okay! Check to make sure that they all work.
If some or all of your LEDs don’t light up, try these solutions:
More firmly attach the legs to the copper tape.
Ensure all short LED legs are connected to the negative side of the battery and all the long LED legs are connected to the positive side of the battery.
Double-check your LED is functioning by sliding it onto your coin cell battery (long leg to positive, short leg to negative).