Follow the path: "Content" → "Add Content" → Select the type of page

Complete all required fields and any additional information you find relevant.

Under the Body section you should provide a short description of the page in the Summary tab.
This will help the search features to properly identify and suggest the page during user searches.

You have the option to save your page as a Draft before publishing, this will generate a preview of the content integrated.
To go back in edit mode, at the top of the preview you will find an "Edit" button.