JD’s already shared with you a possible integration for Ring above.
As for settings codes you can set lock user codes through SmartThings. For basic user codes you can set them using the built in Guest Locks SmartApp.
If you’re looking for advanced features and users like start/expire on (future date), presence based (i.e. codes are activated only if you’re around), weekly/daily scheduled users, user notifications and much more you can check out this app: [RELEASE] Lock User Management (LUM)
There’s also a Ring Alarm Keypad integration available here: [RELEASE] Ring Alarm Keypad (2nd Gen) Device Handler
While this won’t connect to your Ring Alarm (see JD’s link for that), but will allow you to use they keypad with SmartThings.