Time for mistletoe fun! Make sure the cable for the motion sensor is tucked up inside the bundle and that the sensor's lens is clear of leaves. Now, plug in the battery and tuck the case inside the top of the branches. Give the sensor about 30 sec. to calibrate and then try walking under the mistletoe. In a few seconds berries will light up.
Here are some other things to consider. I didn't have to adjust the settings on the motion sensor, but know that there are some listed in the PIR Motion Sensor Guide. Also, my floral tape was dark green, but really a lighter green would have blended better. If the color bothers you, consider dabbing some paint on the tape. Finally, there is a red LED that triggers on the Trinket when the motion sensor is in use. So, just put a small piece of dark tape over it and the magic will stay undiscovered.