Hi,
You can learn from OPEN SAP. It is open source and free e-learning platform powered by SAP. Here is the what you exactly want to learn ABAP FOR HANA course link; ABAP Development for SAP HANA - Dr. Jasmin Gruschke and Jens Weiler
There are lots of videos, documentations in this course. It is clearly easy to understand and apply.
Regards,
Barış Arslan