Unfortunately, smartthings has made the decision that in the new app there will be no way to automatically unlock a lock except by time of day. Or of course open the app and tapping the lock icon.
This is a huge change from the classic app where you could set the lock to unlock for any event that smartthings could recognize, including geopresence or mode. 
( I myself am quadriparetic, so a hands-free lock was the very first home automation project I was looking for. )
We’ve been told the classic app will be removed eventually, but no timeline has been given.
We’ve also been told that the lock decision is intentional for “security” reasons and they want people to use the new “access key” fob instead. But that doesn’t solve my own issues.
So the question is whether you want a multi platform lock so that you will be able to continue to do an automated unlock even once smartthings has dropped the feature.