A screw starter is a hand-held tool that has a small chuck at one end. The chuck opens, usually by twisting the handle slightly and the head of a screw can be inserted. Closing the chuck holds the screw. This is particularly helpful for screwing in tight locations or with very small screws that could easily be dropped. Once the screw is started in the hole a regular screwdriver can be used to finish.
Twist the handle on the screw starter until the chuck opens.
Insert the head of the screw into the chuck. Be sure to line the screw up so that it is straight with the tool.
Close the chuck by reversing the twist on the screw starter handle.
Insert the screw at your project location. The chuck will hold the screw until you are able to get the screw well started into your project.
Release the screw head with a simple twist on the starter tool and use a regular screwdriver to finish screwing the screw.