How and what to prepare for Ethics

Hello Everyone. I am just starting to plan my studies for level 1, Dec attempt. Of all the areas, ethics (as a subject) is most alien to me. I am not found for dry theory anyways. So I am frankly not sure how to handle it. Can anyone please guide me what I should read for ethics like which book, how many times and how much time should I give to this topic. Finally, and most importantly, what should I memorize by words and what things I should just focus on getting the concept.
Thanks.

Note: As I am a student and don't have a tight schedule this semester so I have easy 400ish hours for my whole preparation.