No ladies, this is not a device to help find a good-looking guy. A stud finder is more like a way to give you "x-ray vision", in order to help locate where studs are in your wall for support. The reason for this is because if hung improperly, a shelf or picture frame can rip holes in your wall and/or fall, thus causing damage. Here is how to use a stud finder:
Be sure that the stud finder is fully functional (charged batteries, etc.) and place it completely flush against the wall. Make sure you have a pencil handy.
Start it left of the area where you want to locate a stud. When you press the button it will start beeping. Don’t move it until it stops, because the sound means that it is calibrating to its location.
When it’s all through beeping, slowly move it along the wall. When it reaches the edge of a stud, the finder will beep, indicating that you should mark this spot off with a pencil. Be sure to make the mark as lightly as you dare, to avoid marring the wall more that you have to. Find the other edge and mark it there as well.
When you are all finished finding the stud, you will want to hang your picture right in the middle to give the maximum amount of support.