I shld think you might have trouble: after all, the guy who wrote the book was 69 when he started it, had already been writing since he was 25 years old – and had already written a dozen or more various books.
So that some of the meaning of the book does escape you shldn’t trouble you a bit.
I can though give you some help on your questions.
What you don’t mention is the key to it all: mutinys aboard a ship of war. According to the law of the sea mutiny would be the same as treason – or insurrection on land.
Now what Taggart / whom you call 1st Mate but he wasn’t, he was the Master of Arms, that is, in charge of the guns issued to the sailors as marines) charges Billy with, is mutiny.
Taggart is jealous & envious & desirous of Billy, who is loved in fact by everyone, because he is so handsome, & so gentle. Even the Captain (De Vere) once he knows him feels likewise about Billy – the Captain is certain Billy is innocent.
But the moment Billy, hearing the charge from Taggart’s mouth, strikes Taggart, and thus kills him, Billy has in this other way committed a crime (in ship terms): he has killed an officer, and The Court of Inquiry ordered by the Capt. – a Court Martial – orders Billy hung, from a yard-arm, at dawn. In other words Taggart accomplishes his end – the destruction of Billy – in quite another fashion than he had intended : by his (Taggart’s) own death as in fact murder (!)
So that’s the story. Now, to the other part of your quandary : Why is it all so “important” ? Well, here we come to “life”. Billy is innocence : his name Budd is bud, meaning not yet grown. De Vere the Captain means in fact (in Latin which I’m sure you’ve studied) truth. And truth means conformity to rule; exactness; correctness. Therefore De Vere, despite his love for Billy, & belief in his innocence of the charge brought by Taggart, has to stick to the rules & allow Billy to be hung for the murder of Taggart—or, to put it literally, for striking a superior officer dead! (The “order”, or ‘law’ of the ship is the larger concern – to De Vere as Captain of the ship – than the innocence or reason for Billy’s blow (that Billy has a stammer, & strikes because he cannot speak as fast as he can strike.)
In fact I can, fairly, spell the three characters out in a fashion you would know another way: Billy is Adam, or innocent man; Taggart is the serpent, or depraved man (“original, innate depravity” is what Melville calls Taggart); and Captain De Vere is “father” or, in the judgment sense, in this story, God the Father.
It is a story of life, aboard a man-of-war (a small “World” in itself) and it is this entanglement of the lives of the three men – each obeying their own differences of nature, & belief – which makes up the “Tale”.
OK? That at least gives you the outline of it, and I hope it will help you with your paper (You might also like to know that Melville himself once mutinied—aboard a whaler in the South Pacific; and also, later, sailed 14 months aboard an American warship, the “United States”, from Hawaii to Boston.)
Charles (Saturday November 11th)
Thanks to Charlie Olson and the Maud/Olson Library for permission to reprint. Check out the Maud / Olson Library