How to embed asynchronous code in a page using PhantomJs?

Question

JavaScript

Using page.open() I open the page at the address, then I need to embed the code that:
1) will click on the button.
2) Wait until the new DOM elements of the site are loaded (well, or at least until the specified number of seconds pass)
3) Then work with these elements.
I embed the code on the page using page.evaluate
Here is my sample code:

page.open(url, function(status) {
  
  var elements_array = page.evaluate(function() {
    1)находим элемент кнопки()
    2)генерируем событие нажатия()
    3)ждем подгрузки()
    4)собираем нужную информацию  с элементов по селекторам()
    return elements_array;
  });
console.log(elements_array);
});

I'm doing steps 1 and 2 from the page.evaluate function, but when I try to perform an asynchronous operation (step 3), console.log(elements_array) returns null because the function hasn't been executed yet.
How to solve the problem?