Silverline is a UK based tool company that among other things, sells a very clever tools for setting molly anchors. It’s difficult to find on their website (it’s listed under applicator guns—for foam and caulk) or for sale anywhere in this country—though you can currently get one on EBay or Amazon (for $20 plus shipping).
Why use an applicator gun? Because half the time those little prongs on the back of the anchor spin in the drywall while you are setting the anchor. Buy a big enough box of the right kind of anchors and you’ll be supplied with a little spanner to keep the head of the bolt to keep it from spinning. But the spanners I’ve used are poorly made—as if they had been punched out of the top of a tuna can.
The Silverline Wall Anchor Setting Tool is a much better device. The mechanism looks to be a cross between the handle of a caulk gun and the tools HVAC contractors use to tighten the plastic straps on flexible duct connections. It works like this: Back the screw out about 1/4 inch, put the tool over the screw head, put the anchor through a hole drilled in the wall, and squeeze the handle until the anchor is tight. I haven’t used this tool but it looks to be pretty foolproof. See Ron Paulk demonstrate one in the video below.