Soldering Iron is a tool normally used for applying heat to two or more adjoining metal parts such that solder may melt and flow between those parts, binding them securely and conductively.
Solder is a fusible metal alloy with a melting point or melting range of 90 to 450 degree Celsius (190 to 840 °F), used in a process called soldering where it is melted to join metallic surfaces. It is especially useful in electronics
4. Take the pre-heated soldering iron and solder. Position the PCB wherein you would face its copper side and the legs of the component. Heat up the area to be soldered by gently touching the tip of the iron to the copper surface.
5. Apply the solder onto the joint by gently letting the solder flow into a volcano shape (in a peak style). Make sure the solder flows onto the joint and not around or beside the joint. If the solder makes a dip shape, it is not flowing in the joint and the joint is dry.
6 . Another way to tell that the solder did not hit the particular area is by the appearance of the solder; it will look very dull. When it's a "good solder," it will take on a very shiny appearance.