Plastic wall plugs, or anchors, are used to help place a screw into a surface more securely than just putting the screw in by itself. Plastic wall plugs are commonly used in drywall or brick, where the screw is less likely to be able to hold solidly in the surface. Plastic wall plugs are easy to install and come in various sizes to accommodate different sized screws for hanging or securing objects of various weight. The plugs are often packaged with appropriately sized screws.
Select the appropriate sized screw and corresponding wall plug. The wall plugs will often give manufacturer recommendations, on the package, as to what weight they are designed to manage and what surfaces they are best suited for.
Mark the location of the plug on the surface. Measure with a tape measure and mark the spot with a pencil.
Drill a hole into the surface that is the correct size for the wall plug. The drill size is usually noted on the package. It should be just slightly smaller than the outer diameter of the plastic wall plug.
Push the wall plug into the drilled hole. It may be necessary to lightly tap it into place with a hammer.
Use a screwdriver to insert the screw into the wall plug. As the screw in turned into the plug, the plug will expand to tightly grip the interior of the surface you have put it into. You can now hang your picture or other item on the screw.
Wall plugs are useful for securing items to surfaces, as well as for hanging items. In this case you would screw through the item you are securing, then put the screw through the item and into the wall plug.
Measure carefully. Wall plugs can be difficult to remove once secured in place, and they leave rather large holes in a surface when removed.