How to create a pointer to save the address of a binary tree root and then use this address to call the root?

Hey guys, I have a problem with my seemingly simple code to solve, but I still get confused with pointers.

The code is to insert each digit and operator of an entire parenthesized expression into a binary tree. The logic is, when I find a "(", I fill in the root with "#" and I save the address of this root in a heap to later be used and call that root again and fill with the operator that will be found.

Ex: Get the expression (2 + 3). The root will be "#", then call the function to the left and fill in with "2" and call the function again. When you find "+", call the function to access the top of the stack and get the address saved by the pointer and call the root that is "#" and replace with "+". Then call the insert function again by pointing to the right from this root and filling it with "3".

I did some printing tests and I believe the other functions work correctly. After completing the insert function, I put it to print the root and leave "+", but there are no subtrees because it is the only thing that prints.

Arvore *Inserir(Arvore *raiz, char expressao[], int j, Pilha *PILHA){

char k = '#'; 

if(expressao[j] == '('){
    if(raiz == NULL){
        raiz = Criar_Raiz(k);
    }
    Arvore *ponteiro = (Arvore*)malloc(sizeof(Arvore));
    ponteiro = raiz; // ponteiro recebe o endereço da raiz marcada com "#"
    Inserir_Pilha(PILHA, ponteiro); //insere o ponteiro com o endereço na pilha

    j++; 
    Inserir(raiz -> esquerda, expressao, j, PILHA);} 
else if((expressao[j] == '+') || (expressao[j] == '-') || (expressao[j] == '*') || (expressao[j] == '/')){

    Pilha *TOPO = Acessa_Topo_Pilha(PILHA); 

    raiz = TOPO -> endereco; // pega o endereço (raiz) armazenado no topo da pilha que indica o endereço da raiz a ser usada
    raiz -> item = expressao[j]; 

    j++; 
    Inserir(raiz -> direita, expressao, j, PILHA);} 
else if(expressao[j] == ')'){ 
    Retirar_Pilha(PILHA);
    if (Vazia(PILHA))
         j = 0;
    else{
        j++;
        Inserir(raiz, expressao, j, PILHA);
    }
}
else{ // se for algarismo
    if(raiz == NULL)
        raiz = Criar_Raiz(expressao[j]);

    j++; 
    Inserir(raiz, expressao, j, PILHA);
}
return raiz;
}