G'Day, I got one of these Jumbuck smokers as a Christmas gift, I haven't used it yet and I am yet to learn. I have the same issue, theres assembly instructions, but no info on ' how to use it' . The only place I found some directions was on ' Youtube' . Theres quite few variations of the same thing, and the more videos I watched the more confused I became. Some info is contradicting. But there is an Australian one from a 4WD/camping specialist, that seems informative. You may wish to use that to find some basic info on how to light it etc. , and I guess, like me, it will be a case of trial and error. But I will start off with something small just to get the hang of using it, like ribs, pork belly , butterfly lamb leg, something not too big or thick...in case I mess it up. The one thing that seems to stand out is , don't soak the wood/ wood chips in water. It affects the taste of the meat, and takes a long time before they start to smoke, apparently.
The other alternative, is to contact a BBQ specialist/ retailer and maybe they will be able to help, even if the info is for another brand, but similar type. Hope this helps.

Good luck :)