After registering for the app, all the calls I make from the device are from the secondary number

On your device, the Num2 app is selected by default for outgoing calls. To change the setting (for Samsung with Android 7), you need to go to Device Settings >> Apps. In the menu (click three dots on the top bar) you must select Default apps >> Calling app and make the change there.

Tags: #Outgoing calls #dialing number #caller number # caller ID #dialer from device #caller # outgoing #default number #phone caller