Summarize the following:
Getting too close to the surface can cause drips and runs. Painting too far from your surface causes uneven spraying. Holding the can 10 to 12 inches (25.4 to 30.5 cm) will help the paint job be as even and smooth as possible. Waiting at least an hour will ensure the paint is dry before you apply another coat. You can wait a slightly shorter or longer amount of time if you think the paint takes less or more than an hour to dry. Avoid touching the paint to see if it is dry.

Summary:
Hold the can approximately 10 to 12 inches away from the metal surface. Allow your painted surface to dry for at least an hour.