how to use mysqli_fetch_array

I would like to know how I use this command mysql in my code because I am trying and nothing can not make it work if someone can help thanks.

code:

 $sql = mysqli_query($mysqli, "SELECT * FROM produtos LIMIT $inicio, $totalProduto");
            while($aux = mysqli_fetch_array($mysqli, $sql)){
              $id = $aux['id_produto'];
              $nome = $aux['nome'];
              $desc = $aux['descricao'];
              $preco = $aux['preco'];
              $categoria = $aux['categoria'];
              $img = $aux['img'];
              $tipo = $aux['type'];
              $size = $aux['size'];