Returning Objects in C++ (Binary Tree) - c++

Question

Disclaimer: This is for an assignment. I would like pointers in the right direction (no pun intended) rather than straight code solutions.
I'm attempting to implement a max winner tree (a binary tree in which the node's value is the max of it's children's values, so that the root eventually has the max value of all the bottom leaves). My current MaxWinnerTree initializes a tree full of -1s, just as place holders for values to be inserted later on.
MaxWinnerTree.cpp
#include "MaxWinnerTree.h"
MaxWinnerTree::MaxWinnerTree(int elements)
{
int size = 1;
while (size<elements)
size = size * 2; //gets closest power of 2 to create full bottom row
*a = new Node[size];
for (int i = (2*elements-1); i>0; i--)
{
if (i > elements-1) //leaf
{
//Create new nodes with data -1, store pointer to it in array
*a[i] = (newNode(i,-1,NULL,NULL,NULL));
}
else // not leaf
{
//Create node with data = max of children, store pointer
*a[i] = newNode(i,-1,a[i*2],a[i*2 +1], NULL); //create
a[i]->data = max(a[i*2]->data, a[i*2+1]->data); //gets max
a[i]->right->parent = a[i];
a[i]->left->parent = a[i];
}
}
}
Node MaxWinnerTree::newNode(int key, int data, Node *left, Node *right, Node *parent)
{
Node *n = new Node;
key = key;
data = data;
left = left;
right = right;
parent = parent;
return *n;
}
In my Main, I attempt to create a MaxWinnerTree object to perform actions on (insertion, etc), but I know the way I'm doing it is incorrect. My MaxWinnerTree method doesn't return a value, and the only objects I'm creating are an array and then a linked mess of nodes. As I type this, I'm going to go back and attempt to return a linked list as my tree and go from there, but is this the direction that I should be going in?
Main.cpp
int main (){
bool quit;
int command, elements, binSize;
cout<<"Welcome to assignment 6!"<<endl;
while (!quit)
{
cout<<"Choose an option for the test: 1-> First fit, 2-> Best Fit, 3-> Quit"<<endl;
cin>>command;
if(command==1)
{
cout<<"First Fit!";
cout<<"Enter number of objects: ";
cin>> elements;
cout<<"\n Enter capacities of bins: ";
cin>> binSize;
cout<<"\n";
MaxWinnerTree* tree = new MaxWinnerTree(elements); //Throws x86 error, also throws error when not decared as a pointer
tree->insert(7);
//Irrelevant rest of non-applicable code
In essence, what do I need to do differently to get a tree object that I can operate on after calling my constructor?
Also: I'm shaky on pointers, so if something looks off or bad practice, please let me know.