Here are some sample codes of PHP and Wordpress.
1- File: "wordpress-function-sample.php": some sample codes of the functions WordPress file, of theme support, registration of guterberg custom blocks and custom widgets.
2- File: "wordpress-query-sample.php": some samples of queries for listing posts and custom posts based on categories and tags.
3- File: "wordpress-rest-api-sample.php": code sample when the WordPress REST API was use for listing posts based on multiple arguments. This code may be some of confusing, a few changes during the development of the project were occured.