1. Put a transparent balloon outside, and put a blowing stick in the gap between the two balloons to blow.

2. The balloon outside can be blown up. Grasp the handle of the balloon by hand and pull out the blowing stick.

3. Insert the blowing rod into the inner balloon and hold the outer balloon by hand to prevent air leakage, so that the inner balloon can be blown up.

4. Stretch the balloon handle of the inner balloon and tie a knot on the balloon handle of the outer balloon, so that neither balloon will leak.