Step 1: Disassembling
Step 2: Soldering
For audio cable, you can just cut a audio extender cable.
Soldering wasn't easy for an amateur like me. First, burn thin cables carefully with a lighter so it will remove the protector part over the headphone cables then you are ready to solder.
Step 3: Make It Together!
Voila! Your new bluetooth audio receiver ready to work with all kind of speakers!