Mine did not come with a template. You need to be careful and precise with your measurements.
What I did was measure, mark and measure again, then when I thought I was right where I needed to be, I drilled a very small pilot hole and placed the brackets on the frame where they would mount. I put the drill bit through the hole to ensure that it was centered exactly in the middle of the bracket; adjusting my mark to drill a new pilot as necessary. I think the most I was off on any of the 4 measurements was 1/4" which I was able to adjust by using the above method before I used the hole saw for the final cut.