'How' to use the hardware is simplicity (sorta)...
- Off/four levels of output power
- Modelling light off/(intermediate???)/full brightness
- Optically triggered (very low powered flash on camera hotshoe)
1 specular Main (reflector)
1 diffuse Fill (softbox)
If it works you need a flashmeter, or do a how lot of experimenting trying to determine Full power Guide Number for ISO 100, and by how much each fractional setting reduces output (first assumption is each fractional setting cuts output by -1EV
[edit] reading the owner manual takes so much mystery out of it!!! The optical trigger pulls out of a socket which is also for cable connected trigger...the question is which two pins have to be used to actually trigger the flash!
Guide Number data is provided in the user manual, so a lot of mystery is taken out of that, too.
The doubt that remains is if the unit will FUNCTION...power capacitors are supposed to have power applied to them periodically (every month, every 3 months, every 6 months, depending upon manufacturer recommendation), called 're-forming the capacitor'.
If the unit has been idle for years, either the power capacitor will a) not work at all, or b) work after the unit has been plugged in an left turned On for a few hours, or c) surprise you and work immediately.