Hi, welcome to the site!
Personally, I hate using the term BARF. Many raw feeders are getting away from that and just calling it raw feeding.
OK, where to begin? Raw feeding can be very simple, IE you hand your dog the food, or can get complicated with measurements, grinding and such.(not really that complicated..lol) Your choice. First starting out, many people feed chicken. Its pretty cheap and the bones soft. take a whole chicken and cut it into quarters. Your large guy could probably handle half a chicken with ease. In an adult dog, your aiming for around 2% of body weight, and in a pup, anywheres from 4-10%. Use your eyes as a judgment. If they look heavy, cut back. Too thin, feed more. Simple.
Now, as for choking. Feeding anything to your dog, can cause choking. Ever hear a dog hock while eating kibble? Well they just choked. Thats said, dogs are equipped to swallow bones and raw meat. And don't be surprised if they're fairly large. Its totally normal for them to give it a crunch crunch gulp. So don't let that worry you. Some people grind everything up. IMO, you loose one of the greatest things about raw feeding, that teeth cleaning!
Now for types of meat. Again, you only need 10-15% of the diet as bones, 5-10% as organs and the rest as meat. AND not every meal has to be balanced. Balanced is achieved over a period of time. So for example, I feed beef heart for breakfast. No bones. He got a side of lamb ribs (meaty) for super. When I feed organs i try to add some meat, boneless beef or heart or try to add some bone, turkey necks, chicken necks or backs. I do this as too much liver can cause the squirts.
The diet I feed consists of Turkey necks, boneless beef, organ mix, tripe, mackerel & herring, beef heart, kidney & tongue, beef necks for recreational use, chicken necks & backs. I've also bought some pork when on sale.
Hope this helps. I really recommend heading to your book store and getting a few books.
RAW DOG FOOD: MAKE IT EASY FOR YOU AND YOUR DOG
http://www.dogwise.com/itemdetails.cfm?ID=DN208
Great book.
The other thing, this diet is very easy.