[ How are the wooden sides afixed? ]
The trick is not to drill any holes to the instruments: So I experimented with silicon, normally used in Your bathroom, some years ago. This is a perfect glue. Coat the surface with a thin layer of silicon, the press the wooden parts on the right place of the synth and let it dry over night.
If You ever like to remove the wodden parts it´s no problem. Simply pull them gently apart and carefully cut the silicon, layer by layer, between instrument and wood with a sharp knive. The rest of silicon can simply be rubed off.
The part under the keyboard is fixed on an aluminium plate, which is also sticked with silicon under the synthesizer. You can see this plate on the fotos.
The wood comes from an IKEA “LO”-closet.