[Koha] How to import record from ABCD to Koha

Hallo, Does anybody perhaps have experience with the migration of data records from ABCD to Koha. Our library just implemented Koha as the main Library Management system. However, we would like to import our old records to Koha MARC 21. Your feedback is highly appreciated. Regards, Russel Shihepo Country Training Coordinator- VuFind Namibia