Yes, that link is a good start. You have to use it in order to load the Q2A core from the outside world :)
Then, take a look at qa-include/pages/questions.php file, paticularly this line: https://github.com/q2a/question2answer/blob/4fce0eb2390f56b645dad375d1d81e9f91a97e69/qa-include/pages/questions.php#L64
In there you'll see how the questions are extracted and you should be able to mimic that behaviour in your site manually.
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April 20, 2021: Q2A 1.8.6 released!