How do I transfer the configuration on our existing SBC to the new SBC?

You can do a database backup from the existing SBC, download it, and upload it to the new SBC, validate and recover it:

https://docs.telcobridges.com/tbwiki/Toolpack:Database_Backup_C

https://docs.telcobridges.com/tbwiki/Toolpack:Restoring_a_Database_Backup_C

How dose restoring backup affect license?
Dose it apply license from the backup file from existing SBC or keeps the license that was present on the new SBC?

License is not affected for database backup and restore.