Many people find it hard to read professional philosophy. This is not because philosophy is necessarily harder to understand than physics or art, but because the writings of professional philosophers are generally aimed at other philosophers. They tend not to explain their terms, and make use of copious references to earlier works, and both these tendencies can make their writing inscrutable to those new to the discipline. The best solution is to take introductory courses in philosophy, but many people do not have the time to devote to such a class, and yet are still interested in ethics. Hopefully by reading the books I recommend here you will be able to better understand moral philosophy without having to invest too much of your time in it. Even so you might still have questions, in which case posting them online to a forum, or sending them to a local professor are possibilities.
The first book you should read is The Ethics of Star Trek (amazon). I know it may sound juvenile, but it is actually an excellent book, even if you aren’t a Trekkie. This book focuses on introducing the reader to various ethical theories by applying them to situations drawn from the Star Trek series. It also gives a good explanation as to why philosophers are still searching for objective ethical truths if they aren’t motivated by religious reasons. Why not just be a conventionalist or a relativist? (I won’t spoil the book by telling you here.) Most importantly it is written to be understandable by anyone, even if you haven’t read even a single philosophy book before, which makes it an excellent introductory text.
After you have finished with The Ethics of Star Trek, which should be a quick read, I recommend Moral Discourse and Practice (amazon). This book focuses less on the practical application of ethics and more on understanding the foundations of ethical theories and the practice of moral philosophy. Instead of presenting theories on how to act the book gives theories that explain why we should act ethically, why we should be convinced that ethics are real, and how we could ever hope to formulate an accurate ethical theory without special powers / divine inspiration. Unlike The Ethics of Star Trek, this book is a collection of essays published by professional philosophers. This can make it a slow read at times, and occasionally there may be the need to look something up, but in the end the rewards are worth it.
After reading these two books you probably know enough to make your own choices about what to tackle next. If an essay in Moral Discourse and Practice struck you as particularly interesting or insightful then you might want to read other essays or books by the same author, or alternatively read the works that they cite in their notes. At this point it is more important to follow your own investigations than someone else’s reading list.