Print a diagram on chalk paper on a laser printer. Use a blank paper or a good quality magazine paper.
Make sure the printout matches the electronic components.
Cut the rectangular shape from copper plate.
Smooth the surface with fine sandpaper.
Wrap the prepared plate with paper so that the printed side adheres to the copper. Make sure the paper will not move relative to the plate.
Heat the wraped plate with an iron for about 3 minutes. Move the iron slightly against the edges of the plate.
Soak in warm water to make paper easier to be removed from the plate.
Make sure the paper is completely removed and the imprint remains on the plate. If the print is damaged, wash the plate with solvent and try again. Minor damage can be fixed with a marker.
Place the plate in the etching (B327) until the copper is completely removed.
Wash off the toner with solvent. Drill holes. Use 0.8mm bit for smaller elements and 1mm for voltage stabilizer and button.
Smooth the holes with fine sandpaper.
Place and solder the elements.