Here are some trusted resources that will walk you through many of the core WordPress functionalities and features:
- https://wordpress.org/support/article/first-steps-with-wordpress/
This page provides a basic overview of the initial steps within WordPress - https://wordpress.org/support/article/administration-screens/
This page reviews the WordPress dashboard. - https://codex.wordpress.org/WordPress_Menu_User_Guide
This page reviews how to use WordPress menus. - https://wordpress.org/support/article/wordpress-widgets/
This page reviews how to use WordPress widgets. - https://wordpress.org/support/article/pages/
This page reviews creating and updating pages. - https://wordpress.org/support/article/writing-posts/
This page reviews creating and updating posts. - https://wordpress.org/support/article/wordpress-editor/
https://wordpress.org/support/article/blocks/
These pages review the new WordPress editor, Gutenberg, and various features available.
Please reference this material when getting started with page and post-editing. Many behaviors are repetitive and apply to custom features as well.