Select the largest-diameter toggle bolts that will fit through the mounting holes on the flat screen mounting bracket.
Place the flat screen mounting bracket against the wall in a level position and at the height you want the television to rest when installed. Mark each of the mounting holes on the wall with a pencil, and then set the mounting bracket off to the side.
Drill a pilot hole through the drywall at each marked location. The correct-size drill bit is indicated on the side of the collapsible butterfly toggle bolt.
Remove the collapsible nuts from the toggle bolts. Slide the toggle bolts through the mounting holes on the flat screen mounting bracket, and then thread the toggle bolts onto the ends of the bolts so the nuts collapse over the bolt and not away from it.
Press the collapsible toggle bolts into the pilot holes. When they go though the drywall, the bolts will expand.
Tighten the bolts with a screwdriver. As you tighten them, the butterfly nuts will press against the backside of the drywall and lock the mounting bracket in place.