Automatic search will search all items selected and match AUTOMATICALLY releases, but you need to click the button to launch it-
Manual search will search and display all result for a specific item and let you choose shich one to download (you can by-pass rules like this)
RSS Feed is what you’re looking for, every x minutes, sonarr will read AUTOMATICALLY all the rss you had configured. And if something is matching, AUTOMATICALLY download it.
Thanks guys. Yes that makes sense now. The stuff getting auto downloaded are new releases hence they show up on the RSS feed. These were shows that have been out for a while.