Hear myself up to the punch-in ?

To "punch" in,  and hear the disk playback up until the punch point:

1)  Enable Preferences->Monitoring->Mixbus does monitoring ( not "hardware monitoring" )  (obviously)
2)  Enable Transport->Auto Input  ( this should be on by default )
3)  In the track, make sure neither "In" nor "Disk" is lit;  so Mixbus will automatically switch the monitoring for you.
4)  Create your Punch range,  and enable Punch In and Out buttons.