The card is from an instructable that I got from kate12345. Here's the link: https://www.instructables.com/id/Pixelated-popup-card/
The flowers were created using katmataz's instruction: https://www.instructables.com/id/Origami-Paper-Corsage/
The leaf is from Muhaiminah Faiz: https://www.instructables.com/id/Origami-leaf/
The rest was created as a result of a brain spark and here are the results.
Step 1: Materials
Small sheet of Foam
RGB LED - depends on which setup you use: a premade LED w/ Switch or your own version*
Origami Paper (assortment of colors)
*If you do your own version, you will need the materials found in this instructable: https://www.instructables.com/id/Light-up-Christmas-Card/
Step 2: Flowers & Heart
Then, take a blank card paste the heart on the inside. Take the flowers and hot glue it on the outside where you see fit.
After doing so, it is time to install the LEDs. There are two ways you can do it. The easy way is to buy a RGB LED with a switch already installed. That way, you do not need to do any complex wiring. Once the switch is turned, the light will turn on. Drawbacks with this are that the light doesn't turn on when the card is opened.
The more complex way is to follow this instrucable: https://www.instructables.com/id/Light-up-Christmas-Card/ On this design, the light turns on when the card is opened.
Setting up the LED position is the same in both however. First, I cut a piece of soft white foam in a way that the LED would be able to pass the most light through the pixelations to create a ray pattern. (Before doing so, cut out an area under the Heart so the light can fit through.) After doing so, hot glue the LED in place on the foam. Take the foam and mount it on a piece of cardboard that is the same dimensions as the card. Then, mount that cardboard attachment onto the card itself.
Step 3: Assembling the Card
Then, use electrical tape to cover up the bottom and side areas that are exposed so that you have a nice trim.
You are now done. Enjoy your creation and give it to someone special!