Stitching It Together
If you need help sewing with conductive thread this tutorial covers the basics.
Cut a long piece of conductive thread, thread the needle, and tie a knot at the end. Sew your first connection: starting from the positive sew tab of the battery holder, connect each of the three LEDs with a running stitch and three loops of conductive thread around each positive (+) sew tab. Tie and cut your thread.
Finish your line of stitching by tying a finishing knot on the last (+) sew tab and trimming any excess thread.
With a new piece of thread, repeat the process for the negative side of the circuit – connecting the three LEDs’ negative sew tabs to one another and, finally, the negative sew tab on the battery holder. Tie a finishing knot, and trim any excess thread.