To Edit a page - you must login to your website and choose the page from your All pages.
Select Edit with Divi
Utilizing the different column formats, the page has better flexibility and use of space for each web page.
Example to the right indicates a Text module in a three column row with three types of modules possible.
The text module can be used to create a small bit of text within a complex layout, or it can be used in a full width column to create an entire page.
To Insert Text module click on the link: Text module