Open Settings from the Bloomkeeper menu. Everything you can change about how Bloomkeeper works for your shop is in one place.
Add the email address the digest should go to and Bloomkeeper sends one summary a day of everything waiting for your approval. If nothing is waiting, you get nothing. It will not email you for the sake of it.
This is the setting most worth turning on if you are in Guided Approval or Alerts Only mode, since it means you do not have to remember to check.
Switching modes does not undo anything already done or approved. It only changes what happens from that point on. Moving from Auto back to Guided Approval is a perfectly normal thing to do if you want a closer look for a while.
The full Bloomkeeper Terms of Use and privacy information are always available from the menu under Terms of Use.