Buy a battery, or use a battery car if you have one.

Find someone who knows something about circuits, but they are all learned in school. The most basic thing is to buy a few high-power LED flashlights, not LED lights, and the effect is not good, and buy some mirrors.

It is best to charge the flashlight, connect the flashlight directly to the battery, and then put mirrors in different positions to reflect the light.

The second method, if the audience is not high, is to buy a battery, buy several rechargeable flashlights, put the battery and flashlight in the middle of the audience, the flashlight shines upwards, and find a reflector (such as A3 paper) on it, which will reflect a larger light area.