Soldering is an electronics process join together two or more metal by melting and flowing a filler metal (having a relatively low melting point) into the joint. In other words, you use a metal that has a low melting point to adhere the surfaces to be soldered together. The filler metal used in the process is called solder.
Tools that you need for soldering is electric soldering iron, which has a variety of tips and the soldering gun, which typically provides more power, giving faster heat-up and allowing larger parts to be soldered.
The video below shows you how to do a basic soldering.
video by cuffer