Purchased varying 1 gang and 2 gang low voltage screw-in type brackets as seen here.
Upon inspection they appeared to simply sit in the wall with the the screws being screwed into the side of the dry wall; however that seems incorrect as now having seen this image.
Confusion has surfaced as the end goal is to install this and since this is an existing installation my concern is that I might have purchased a bracket geared towards a new install.
So...how do I install these brackets in an exiting drywall installation without having to use a stud or should I use a different type of brackets?
If somebody wants to add a bracket tag and re-tag the question that would be great.
Looks like this is what I should have purchased; will await confirmation from the experts.