Showing u how I install chicken(button) lights on my dry van trailer but will do same concept on anything u can put hole and lights. I started by putting a piece of tape in the general area I wanted to put the lights. Step back look at spacing and make sure it’s good. Then I measure center of the space when light was going and measured up 2.5” from bottom of trailer. Put a dot on the 2 lines and drilled a 3/4 hole to fit the rubber grommet and light inside.