How to Edit a Page
After logging in, visit the page you want to edit. In the top right of the page, select the gear icon to view the admin drop down.
Select "Edit Page" to both check out the file and open it for editing. Editing tools will now be displayed in the ribbon.
As you are editing the content of the page, frequently select the "Save > Save and Keep Editing" option from the dropdown at the far left of the ribbon to make sure you don't lose your work.