WordPress can be used in a variety of ways, so there's no one answer as to how you can do things. In many cases there are multiple ways to achieve the same goal. But, there are common uses:
Non-technical users often install WordPress and then install and configure premade plugins and themes. Themes control the look and feel of a site, while plugins add or change functionality. Usually little to no coding experience is required to use these. In many cases, you can find a way to achieve your goals without having to code anything.
In any case, any content you want to publish is created by logging into your site and adding or editing Posts, Pages, or custom post types. Posts and Pages come standard with WP Core; some themes and plugins add custom post types, and you can also create your own custom post types. Again typically it's best to get used to the Core post types first, and then you can build things out further if needed. In addition to publishing content, many themes also support things like custom menus and widgets. You may just want to start playing around, and possibly create a development site - not the live one, but a local copy - to experiment and see what's possible and what you may want to do.
WordPress.org documentation is a good place to start.