Soldering is a process of joining metal components like in electronics where a filler metal with a low melting point called solder is melted and flowed into the joint between two metal items. The key steps of soldering include preheating the soldering iron, inserting electronic components like resistors into printed circuit boards, heating the joint with the soldering iron, and applying solder to allow it to flow into the heated joint in a volcano shape to securely bind the components conductively. Solder has a melting point between 90 to 450 degrees Celsius and is especially useful for electronics work.