Normally they are mounted beside/around/behind the LCD screen I believe. But if your's isn't already there.. It could be risky business if you don't know what your're doing.
I would say just mount it anywhere you can get it, as long as you don't short anything out with the metal/glue/screws... And the screws probably aren't even required, just use some of the 2 sided tape.
Just put it in somewhere where you would get good signal.