Kevin,
Welcome to JavaRanch!
Indenting is necessary because it makes the code easier to read. Suppose I have the following two code snippets:
In (a), it is obvious that do stuff only occurs when i is 0. In (b), it takes longer to figure that out. The impact of this becomes larger for bigger chunks of code. So everybody indents to make life easier.
Basically, you indent everytime there is some control structure, such as a method, loop or conditional. (If you don't know what these are yet, you'll learn soon enough.) The JavaRanch
style guide also gives some tips.
Closing brackets end a method/loop/conditional. In small programs, they are at the bottom of the page because that is where everything stops. In larger programs, they can appear earlier. (Quotes are the symbol at the end of a string.)