I, as well received a side burner for Christmas. Although I had to order it myself, I got what I wanted!
Mine didn't come supplied with instructions, but taking a look at it, seems like there is nothing to it to get it installed.
I did run into one small problem with the arm braces....where they connect to the burner shelf, the bolts supplied would not fit into the holes. There are two nuts welded onto the bakcside of the holes, and mine didnt seem to line up. Instead of going through the hassle of sending mine back to Char-Griller to get a replacement, I just went to Lowes and bought two more nuts and bolts that would fit. It just seemed like the easiest thing to do.
As far as the BTU, i'm not real concerned about it because I am just probably going to use my side burner for starting my chimney. If I want to cook some beans or heat some sauce, I don't mind doing that inside on the stove.
Hopefully within the next day or two I will finish installing it on my CG and try it out.