Here are the steps to make a Bluetooth speaker:

1. Prepare your speaker box by cutting it down to size and making sure it is clean and free of debris.
2. Download and prepare the files for 3D printing.
3. 3D print the Bluetooth speaker box.
4. Finish and paint the 3D prints.
5. Connect amplifier to speakers.
6. Connect battery to charging system.
7. Connect amplifier to charging system.
8. Put all components into the box.

You will need the following components to make your custom Bluetooth speaker:
- Two small speakers
- Bluetooth amplifier board
- Battery charging system
- One or two rechargeable 18650 batteries
- 3D printer and filament (you could use wood instead, however)
- Assembly tools (wires, screws, a screwdriver, superglue, and soldering iron)

Here is a tutorial that goes into more detail on how to build your own Bluetooth speaker: