How far have you got, and where are you stuck? Can you perform the task on paper?
Do you know how to store 10 integers?
Can you write a loop that sums 10 integers using both even and odd indices? Then you could modify that to add up just the odd ones.
What do you think is the difference between using a loop and not using a loop? If you didn't know in advance the number of integers to add up, how do you think you might do that without a loop?