Answered: How can i use qa-app-posts.php to insert a lot of questions to the DB?

The basic structure would be like this:

<?php
require_once '/PATH/TO/qa-include/qa-base.php';
require_once QA_INCLUDE_DIR.'app/posts.php';

$questions = ]; // do something here to get your list of questions

foreach ($questions as $question) {
    qa_post_create('Q', null, $title, $content, $format, $categoryid, $tags, $userid);
}

The variables like $title would come from your questions array, so it may be $questions'title'], $questions'content'] and so on. If you don't have a user ID to use then use null and they will show as anonymous.