I think the very best way to learn how to cook a delicious and original Ethiopian food you better learn it from local people.
Especially recommend you very local restaurant without proper sign board normally small shop selling Ethiopian coffee, they are small size and you can learn if you show great interest without paying anything but your own food. From my own experience, using olive oil and local oil makes great difference. Local oil is much better taste! For this purpose much better to learn from local people, not Internet nor books,, I tried these ways but learning from local people is best way!