Wikipedia is surely as confusing as possible on this subject. I have printed but not yet read an essay by Suzanne Haik-Vantoura. Here is my initial summary of the signs, the names, their supposed role in the text, the role of the signs under the words in the music and the role of the signs above the words. There may be some differences in the poetry and prose that I am ignoring in SHV's thesis at the moment. Just learning at this stage. Hit ctrl+ to enlarge. Con = con junctive, dis = dis junctive, I=Independent disjunctive - whatever that means. At the moment I don't see much help in these terms, apart from the obvious verse and half-verse markers. (Something does not support the Unicode for this, so I have had to use an image). More official interpretive chart here.
Ornamentation is relative to the current note that the singer is on - I have shown it with B as example.