Just press in along the wall. You will find where it bows in the most and the least/not at all. Do not use screws longer than 1&1/2” except to allow for any mounting board depth.
Most mount a board across at least two studs to allow more positioning options.
I mounted an articulated arm mount for a 21” LED lightweight television. So I used two short lag screws into an exterior wall stud.
That was my second location. First location, with same arm, was on the end of the kitchen cabinet. I reinforced the panel & frame inside but people kept hitting their heads on theTV ;(