Ok, take deeeeep breath.

Raw feeding is not hard but you do have to do some figuring.
First off, you never by NUMBERS of things. You feed by the WEIGHT of things.
First thing you need to know is his weight. Since he's 5 months old and still growing I would recommend starting at about 4% of his current weight. That is the total amount (in WEIGHT) of what you will feed each day.
So, here's the figuring part:
Dogs weight * 5% = total weight of food each day
For example, let's say your dog weighs 50 lbs. THIS IS JUST AN EXAMPLE.
50 lbs * 5% = 2.5 lbs of food per day
Now, you need to take that amount and divide it up by the different TYPE of food you will be feeding - RMB (Raw Meaty Bones), MM (Muscle Meat = meat without bone) and OM (Organ Meat - like liver or kidney).
Here's what I recommend: 50% RMB, 45 % MM and 5% OM
So, using the EXAMPLE above here's what that breakdown would be:
2.5 lbs * 50% = 1.25 lbs (that's 1 lb and 4 ounces) of RMBs
2.5 lbs * 45% = 1.125 lbs (that's 1 lb 2 ounces) of MM
2.5 lbs * 5% = .125 lbs (that's 2 ounces) of OM
So now you just have to replace YOUR dog's weight in the figuring and go from there.