These videos will get you started. They show you the admin panel, how to create pages and posts, add images and use the basis editor function.
Using Page Builders
If you want to create fancier pages and posts, you might want to use a 'page builder.' Guttenberg is the page builder that is already built into WordPress for you and is automatically included when you create the website using WordPress.
Beaver Builder and Elementor page builders are premium plugins that may need a bit more learning, but usually create a better result and are easier to use in the long run, especially if you are adding images and specialist features to your page.
These videos include SEO (Search Engine Optimisation) techniques for WordPress.
There are also videos about the more advanced plugins for WooComerce and Gravity Forms.
WooCommerce is a complex group of plugins that enable you to create a shopping cart as well as more advanced features to monetise your website.
Gravity Forms is a plugin that creates complex forms, survey, 'pizza builders,' and more.