If your electrical box itself is loose within the wall, you have a couple of options. The first is to use a wall plate spacer that basically clamps the electrical box to your drywall to prevent ...

The thickness of the stud will depend on the application, if it's an interior or exterior wall. Exterior wall studs are thicker to allow for more insulation,” says Lord-Levitt.

Once you think you’ve identified the stud location, use a 1-inch-long finish nail, which is small and thin so it won’t make a large hole, to tap into the wall.