Hi! To change the "From" email address, hop into your automation workflow via the edit button. In the lower section of your screen where you see "... SEND THIS... (Content)", you'll want to click on each campaigns orange envelope button. This will bring out a pane on the right where you'll be able to change each mailings "From" info.
Hope this is easy for you. Reach back out to let me know weather or not if this was helpful.