Add content in the TYPO3 backend
The pages generated in step Create initial pages already contain some example content.
You can add additonal content in the backend. Go to Web > Page and select any of the pages you created before, (for example "Page 2"). Click the + Create new content button in the column labelled "Main" and choose the "Regular Text Element" content element.
Enter a headline and some arbitrary text in the Rich Text Editor (RTE).
Save your changes by clicking button Save at the top. You can return to the previous view by clicking Close.
Preview the page by clicking button View webpage.
Check that the content is displayed as expected.
Whenever you edit the content elements on a page the cache of the current page is automatically deleted. If the content fails to update you should still delete the TYPO3 caches and force your browser to reload.
There are many tips and tricks around content editing. The topic is described in more depth in chapter Content Elements of the Editors Tutorial.