Welcome - the quantitative reference is the amount of the main product (or waste treated) of a process, and all other amounts are to be seen in relation to the amount of the quantitative reference. So, if the qr is 2 pieces of cars produced, all other inputs and outputs reflect that, so e.g. you have steel, cables, ... to produce two cars.
So, I have to set directly the values of the other flows considering the production of 2 items - yes exactly.
It is however a bit archaic because as of today, LCA processes are linear input / output systems, and thus any of the inputs or outputs could be selected as the quantitative reference, and be used to scale then the other input and outputs.
It is a useful convention to set the amount of the quantitative reference to 1, which makes comparison of different processes that are producing the same product easier.