Hi Onalenna,
the program looks promising. But you did 2 task in your for-loop in each step. First task: you scan in the integer (line 13) and second task: you build the sum (line 14).
So you should separate the tasks and use 2 for-loops. One for the first task, and one for the second task. You can do that by copying the whole loop (line 11 to 15) and place the copy right below the end of the loop. Then delete the second task (sum) from the first for-loop. Then delete the first task from the second copied loop.
So, now that you have the 2 tasks separated, you can just put the second loop into its own method easily, as described in your assignment. If you are using Eclipse, it will do it for you automatically by marking the second loop as selected, then right-click --> refactor --> extract method.
And if you want to become professional, then you can clean-up a bit and replace the second loop with a newer for-each loop