You have 2 different possibilities to achieve that:
a.) Click in the menu on "Pages" => "Manage pages" and an overview of all of your pages and folders will be displayed.
When you now click on the name of the page or the green pen icon on the right, a comfortable editor will open, where you can add content to your page.
If you want to edit pages that are located in subfolders, please just click on the folder icon and then edit your page as described above.
Tip: In order to be able to find pages quicker for editing, we have added a useful search feature. You can search your pages by any text located in the title or content.
In addition, for a better overview, there is a browsing features for your pages.
b.) At "Menu" => "Manage menu elements", you can easily get to the edit page form by clicking the green pen icon at the appropriate page.