How to pack a classic woolly DIY soft Rucksack for Hiking making it stable and comfortable to carry

Yes I know, the classic woolly Loden Alpine hunting rucksack has no frame nor a solid backplate to give the pack any ridged shape at all, but still allowing to carry a 20Kg load over a longer period of time.
But, yes, there is a very easy solution for that. Just pack it the right way, and this sort of out of date rucksack system can be easy made suitable for long-term Hiking without compromising on comfort.