First of all, the soldering iron head is pasted on the welding spot, and the electric soldering iron needs to be at a certain angle, so that the melted tin can accurately cover the solder joint. howeverAfter that, the soldering iron head shall stay at the solder joint for 2-3 seconds. After welding, hold the component in your left hand, remove the electric iron, and wait until the tin on the solder joint cools and solidifies before weldingRelease the left hand. Use tweezers to try to turn the lead to make sure it is not loose, and then use tweezers to cut off the excess lead