Click or tap anywhere on the screen and a firework rises from that spot. The more you keep pressing, the more bloom at once. Use the Color, Motion, Shape, and Environment panels to fine-tune how your fireworks look.
Drag the heading at the top of a panel to move it wherever you like. In the Environment panel you can toggle auto-launch and the starry sky. From the Output panel, you can save your finished fireworks as PNG or SVG images or a WebM video.