The makeup referenced here was done by David Woodruff if I recall correctly.
It looks to be a multipiece silicone appliance makeup. I don't want to discourage you, but doing it how it was done here would be very advanced for a beginner. You'll need a life cast, understanding of sculpture, sculpture break down, snapping positives, and molding. Running silicone and encapsulate itself is also an art form which takes some time (and money!) to learn.
A much more beginner friendly and less costly way to go would be using gelatin to build up the scarring. (You could also use a silicone like 3rd Degree or Skintite to do the same type of build up, but it would be a lot more expensive.)
There are quite a few YouTube tutorials on gelatin build ups, scars and burns and such. I'd suggest searching around and watching a few to see if it's something you'd feel capable and comfortable doing.
Good luck!