There are a few ways to do this, but here's one way:
1. Cut the LED strip light to the desired length and peel off the backing.
2. Twist each end of the LED strip around a connector (or use pliers).
3. Strip about 1/4" of insulation from each wire and twist it around the corresponding connector screws on the battery pack (or use a screwdriver).
4. Close up the battery pack and test your new LED lights!