Share 'Help with making stock'

I bumbled through making stock the other week -- for the first time, following the instructions in Nourishing Traditions. Well, trying. I was left scratching my head a bit, going 'but what does that MEAN?'. Happily some things are just working better second time around, but I'd still be grateful for some advice.   1. So I understand that it's really important to skim the scum that forms when you…