Steps:

1. Solder the part and connect.

2. Connect it to your cell phone.

3. Test it.

Product list:

13007 amplifier　https://www.utsource.net/sch/13007

bc547 Amplifier　https://www.utsource.net/sch/bc547

bd139 amplifier　https://www.utsource.net/sch/bd139

More details, pls check the video on Youtube: