A prefab barrel or cabin sauna is built from numbered panels meant to disassemble, much like a garden shed kit, while any sauna with hardwired electrical heating needs a licensed electrician involved before you unplug or uninstall anything.
Pro tip: Photograph the internal wiring path behind infrared panels before disassembly, even with an electrician present, since it saves real time on reinstall questions later.
Watch out: Never disconnect a hardwired sauna heater circuit yourself; this is an electrical panel-level disconnection that should go through a licensed electrician, both for safety and to avoid code violations.