Emily, how old is he?
I have 4 children. We have always used just whatever meat we were cooking for the family meal. Make sure he gets a better-done piece if it's beef or lamb.
Cut it in tiny pieces, or for the first time or two, whiz it briefly in a blender/food processor with a little water, just to break it up a bit. Although it seems like mince would be an ideal first meat, it's actually one of the more risky ones. Since it's been handled a lot, there is a slightly greater chance of bacterial contamination.
TMI perhaps, but my dh's favourite way is to make what he calls "pre-gurge"! He takes a small piece of meat, chews it up and then puts it in the baby's mouth. I have to say they love it. Also, because it has his adult salivary enzymes on it, it's easier for them to digest.
As far as amount, just follow his lead. Offer 2-3 tiny pieces. If he eats them eagerly, then offer more. My babies often went in spurts. They would eat an amazing amount of something at one meal, and then little of it for a day or two. Then back "on" again.
If you are going to season or salt the meat for yourselves, just set aside a little for him that is plain. If he tries your meat and likes it, so much the better. An Indian friend always reminds me that millions of babies around the world eat spicy food and like it!
Have fun....