Ron,
When I did mine a couple of years ago, I took the plastic insert out of the bumper and sawed off a portion of the cone to make the hole bigger. Then I built a metal bracket that bolted to the bumper and provided a place for the mounting bracket that comes with the light to fasten to.
Took about a day to get the lights mounted. The brackets I made required some cutting, bending, drilling, and light welding of some sheet steel by the time I was done. Not real complicated, but it took a little time to work it out.
I know. You're going to ask for details. I think I still have the write up somewhere on the computer, and a few pics. I'd have to look them up.
-Jay