Ask half a dozen Scots how to make stovies and you'll get half a dozen different answers! Ingredients vary from region to region and family to family but one thing without which you cannot make stovies IMO is leftovers! It's the traditional Monday meal because it uses up what's left from Sunday lunch. Lamb is best, but beef is OK. Can't imagine stovies made with pork or chicken, but there's no culinary reason why they couldn't be.
So, dice the lamb and slice the potatoes. Take a large onion, peeled and sliced, and brown it in melted dripping. When the onion is soft add the lamb with salt and pepper but don't go mad with seasoning - Scots food isn't supposed to be spicy. Cover with layers of the sliced potatoes and then cover with stock. Oven back for three quarters of an hour or so or until the stock is absorbed and the potatoes are turning brown.
Stove is Doric for stew, so that's what you're aiming for... :-)