At the heart of any normative moral system there will be a basic rule, or set of rules, that makes clear what our obligations are. We call these basic rules 'Moral Principles'.
The basic problem in Normative Ethics is that there is no agreement among ethicists as to which principle (or principles) is the right one. Different philosophers have put forward very different principles that they think should govern our action. Because of this controversy about which moral principles we ought to follow, ethicists have agreed on some basic minimum criteria necessary for any potential moral principle to be accepted. If a candidate principle does not meet all, or even most, of these criteria, we can doubt its validity as a good moral principle. BUT, just because a moral principle meets these minimum criteria, does not mean it will be a good moral principle. However, if it fails one or more of these criteria, we have good grounds for thinking it's not a good principle.
Having our five criteria in place, we can now move on to the different types of normative systems. Again, at the heart of each of these systems there will be a basic moral principle or set of principles which are designed to guide us in our actions.
Once we've decided what a moral principle is, how do we decide which ones to follow? We need a systematic theory that tells us which principles we ought to adopt. Over time we've seen the development of three basic types of ethical theories, each with it's own (i.e., unique) set of moral principles. The hard question is, which type of theory should we adopt?
Each of these types, or families, of theories represent a general approach to resolving the normative question: How should we act? However, there are variations within each of these general types which is dramatically demonstrated by the Ethics flow-chart you should have downloaded. For example, while Ethical Egoists, Hedonists, and Utilitarians all agree that moral obligations are determined by good consequences, they differ as to what a good consequence is. That is, while we might agree that a right action is one which insures a good outcome, what counts as a good outcome (a good consequence) may be less clear.