http://www.waynesworlds.org.uk/id73.htm the above site gives a good idea of what you need and how to do things . The commercial way is different and involves all sorts of chemicals and processes. The way outlined in the link is more or less how I have done it in the past. I did a few sheep skins and even a badger ( found by the side of the road ) . When I get my own sheep , I will follow this way of doing it . Dyeing , I would imagine , would be done after curing , with any of the common wool dyes available .
I used to work in a skin and hide processing place. The main thing you must do when you get your skin is rub plenty of salt into the wet side of it, until you are ready to cure it. This is maybe best done as soon as you collect it . In hot weather they start to go OFF very fast. Salt it, rub in well and then pop it in a plastic bag or two till you get home. Make sure you unroll the edges, two big scooped handfulls per sheep skin will do the job and then rub it in well . Hope that is of help ...cheers Russ...