How to wait for chrome.tabs.executeScript element to load?

Question

JavaScript

I write extensions for chrome. When you click a button in a popup, you need to click on a button on the site, wait for another button to appear, click on it, wait for the form to load and enter text into one of the inputs.
The problem is that chrome.tabs.executeScript executes the code asynchronously, so the script tries to click the second button almost as soon as it clicks the first one.
How to make it wait for the element to appear?