I need to set rules for certain classes and objects for push notifications. How can I do that?
There are no separate notification rules for push notifications: they are sent for the same events as email notifications except for digest messages. So, you would set up a notification rule like usual and if you have push notifications enabled, the users will receive these notifications via both email (if they have an email address associated with their login account) and their mobile device (if they have M-Files Mobile installed).