Select "Manage Blocks" from the leftmost navigational menu, entitled
"Common." This will lead to the "Manage Blocks" page, which contains
a list of blocks that currently exist on the website.
Navigate to the desired block from within the list of pages (ie.
Left Block).
Select the "Edit icon" that is located to the very right of the name
of the page. This will lead to the "Edit Block" screen.
Scroll to the bottom under the "Contents" header, where the textfield
"Contents" is. Edit this textfield as desired.
Click "Save Changes" when the edits have been made. The block should
now be updated on the website with the new content.