If you have multiple LED strands, plug them into each other to create one long überstrand.
Each strand should have a pair of extra wires with exposed ends, for connecting power. Only one of these pairs is required. The rest should have their exposed tips trimmed flush or covered with tape or heat-shrink tubing to prevent electrical shorts.
For 1 to 3 linked strands, let’s use the pair of wires at the end. For longer strands, choose a pair near the middle.
Find the silver stripe on your diode.
Diodes have a specific polarity, passing current in only one direction…the silver stripe is the + end. So we want to connect the + side of the screw terminal to the “dark” end with no stripe.
Bend the diode's leg on this side and slip it into the port on the screw terminal. Solder the other leg to the RED wire coming from the LED connector.
If you don’t have a 3-pin JST plug, and you’re 100% okay sacrificing the “output” end of your LED strand, you can cut that plug off and use it as an input-end adapter. Do this at the mid-point between the plug and the last pixel, so there’s enough wire to be useful. Was your DC jack connected to the extra power wires there? That’s okay! Remember, the strand can accept power from either end.
If you're doing this project with kids, you can use alligator clips instead of soldering. It won't stay permanently attached, but it's a fun and easy way to get the lights up and running.
Clip the 3d printed flowers gently onto each light. If they don't seem to fit right, turn them 90 degrees -- the spacing between the clips is not exactly even; the wire goes between the wider clip spacing.
If they still don't quite want to fit, use a heat gun on the clips for just 5-10 seconds to soften them a little bit, then press the flower onto the light. When the plastic cools it will grab and hold nice and tightly.