Position the kick plate on the face of the steel door where you want to install it. Most kick plates are made with predrilled holes in their faces. Transfer the location of these holes to the face of the steel door.
Drill pilot holes into the steel door to accept your screws. The size of a pilot hole is much less flexible in steel than in wood. It needs to be exactly the size of the shaft of your screws, not counting the threads of the screw. A pilot hole this size allows the screw to enter the steel but is small enough that the threads of the screw engage with the edges of the pilot hole and hold tightly.
Screw the kick plate onto the steel door by driving metal screws through the holes in the kick plate and into the pilot holes in the steel door.