SIMD the following code

How do I SIMIDize the following code in C (using SIMD intrinsics of course)? I am having trouble understanding SIMD intrinsics and this would help a lot:

int sum_naive( int n, int *a )
{
    int sum = 0;
    for( int i = 0; i < n; i++ )
        sum += a[i];
    return sum;
}