Heap vs Stack allocation

I am alittle bit confused on topic of allocating objects on heap vs allocating on stack, and when and how delete() should be called.

For example I have class Vector. I would like to make an array of these.

I could either do this

Vector** v = new Vector*[100]; //create an array of 100 pointers to 100 Vector objects

This as I understand would allocate everything (well except pointer addresses) on a heap? So to free memory I would need to:

for (int i = 0; i < 100; ++i)
{
   delete(v[i]);
}
delete(v);

OR just

delete(v);

is enough?

Now another example:

Vector* v = Vector[100];

Whats happening in this case? Where does allocation happen? Heap or stack? Do I still need to call

delete(v);

But this is not all question, sorry for long post..

example:

class Vector
{
  int x, y, z;
}

Vector* v = new Vector();

wheres x, y, z allocated? Heap or stack?

or how about this:

class Vector2
{
   int items[10];
}

Vector2* v2 = new Vector2();

where are items[10] allocated? How do I delete v2? Do i need custom destructor?

Also last but not least how about this one:

class Vector3
{
   int* items;
}

Vector3 v3 = Vector3();

Where is items pointer stored? heap or stack? How do I delete this?

Thanks and sorry for long question. Ive been having trouble with this stuff for long time and couldnt really find any complete explanation on line.