To make a change to a page that already exists is probably the most common task of all. It invloves multiple side-tasks. Links are provided for assistance.

1. Sign In. 
2. Navigate to the page you wish to update. If you have editor permissions on that page you can...
3. Click the EDIT button on that page.
4. The editor view of the page shows all of the APPs on the page and the regions in which they reside. Determine which APP contains the content that needs to be updated.
5. Edit that specific APP according to the instructions for that APP. (see a list of all APPs)
6. When you have completed the update, SAVE the changes in the APP, but don't forget to SAVE the page as well.