Please help me with 2D Arrays

I am a newbie to computer science, and I am having difficulty understanding my professor's instructions. This is what it is:

1. Declare a double array size 100.

2. Fill out the array with 1 if a random value is greater than 0.5 else 0

3. Print the number of 0's that are in the array

And I have been stuck for hours, with no clue how to do it, tutoring center is occupied...

 public class DoubleArray {

 public static void main(String [] args) {
 double [] a = new double[100];
    for (int i= 0; i<a.length;i++)
    if (Math.random()>0.5)  {
      a[i]=1;
      System.out.println("1");
    }
    else a[i]=0;
    {

      System.out.println("0");
    }
 }
}

I know this is wrong, as it doesn't even include the counter of 0's, but I have no idea to use random numbers, and an array, and a for loop, and if/else, and a counter all at once.

Please help as much as you can :(