New to Java

I would like some help with a question on arrays

I am supposed to find the mean and the mode of a 2 D array

I created a nested for loop the totaled the array = that to int total

and then I set int average = total / array.length, and it is not correctly averaging the array,

my professor said that array.length won't work for a 2D array only a single array. she suggested a counter but I am not sure on how to code this?

Can someone help me please?

I have no idea on how to find the mode.