You have not mentioned the Netbackup version. You may check the NBU 7.0 Exchange Admin guide page 152 which gives the required information
All covered in the Exchange Admin Guide but a useful resource is here:
This covers how it should have all been configured to make restores work - so check through this first.
If you have followed this then a restore should work fine - just run the restore from the BAR GUI on the Master server
Hope this helps