Since there are only 11 possible outcomes (2…12 inclusive), we can enumerate them with the number of ways they can each be formed:
Outcome    # ways          
2                     1
3                     2   ((1,2) or  (2,1) on the roll of two dice) 
4                     3   ((2,2), (1,3), (3,1))
5                     4   ((1,4),(2,3),(3,2), and (4,1))
6                     5   
7                     6
8                     5
9                     4
10                   3
11                    2
12                    1
                     ———
                      36 possible outcomes
The probabilities are then just the (# of ways for a given outcome) / 36.
For instance:
  rolling a 2 has probability  1/36 
  7 is the most likely outcome, with probability  6/36 = 1/6
You can compute the rest similarly.