How to weld the circuit board of Hewitt Bluetooth 139 earphone?

1, manual welding. Weld the bonding pad with an electric soldering iron, then clamp one end of the chip assembly with tweezers, and fix the other end of the assembly on the corresponding bonding pad of the equipment with a soldering iron. After the solder cools, take out the tweezers. Then solder the other end of the assembly with a soldering iron, and the circuit board of Hewitt Bluetooth 139 earphone can be soldered.

2. Make a stencil screen welded by machine, print solder paste on the circuit board, and then install and place the welded chip components manually or by machine.